Spring Boot详解
SpringBoot基本应用：
<?xml version="1.0" encoding="UTF-8"?>
< projectxmlns = " http://maven.apache.org/POM/4.0.0" xmlns: xsi= " http://www.w3.org/2001/XMLSchema-instance" xsi: schemaLocation= " http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-
4.0.0.xsd" > < modelVersion> </ modelVersion> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < parent> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> </ parent> < dependencies> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> </ dependency> </ dependencies> < build> < plugins> < plugin> < groupId> </ groupId> < artifactId> </ artifactId> </ plugin> </ plugins> </ build> </ project>
package com. lagou. controller ;
import org. springframework. web. bind. annotation. RequestMapping ;
import org. springframework. web. bind. annotation. RestController ;
@RestController
@RequestMapping ( "hello" )
public class HelloController {
@RequestMapping ( "/boot" )
public String helloBoot ( ) {
return "Hello Spring Boot" ;
}
}
package com. lagou ;
import org. springframework. boot. SpringApplication ;
import org. springframework. boot. autoconfigure. SpringBootApplication ;
@SpringBootApplication
public class SpringBootDome1Application {
public static void main ( String [ ] args) {
SpringApplication . run ( SpringBootDome1Application . class , args) ;
}
}
package com. lagou. controller ;
import org. springframework. web. bind. annotation. RequestMapping ;
import org. springframework. web. bind. annotation. RestController ;
@RestController
@RequestMapping ( "hello" )
public class HelloController {
@RequestMapping ( "/boot" )
public String helloBoot ( ) {
return "Hello Spring Boot" ;
}
}
server. port= 8888
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> < scope> </ scope> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < scope> </ scope> </ dependency> package com. lagou ;
import com. lagou. controller. HelloController ;
import org. junit. jupiter. api. Test ;
import org. junit. runner. RunWith ;
import org. springframework. beans. factory. annotation. Autowired ;
import org. springframework. boot. test. context. SpringBootTest ;
import org. springframework. test. context. junit4. SpringJUnit4ClassRunner ;
import org. springframework. test. context. junit4. SpringRunner ;
@RunWith ( SpringRunner . class )
@SpringBootTest
class Springbootdome2ApplicationTests {
@Autowired
private HelloController helloController;
@Test
public void contextLoads ( ) {
String s = helloController. helloBoot ( ) ;
System . out. println ( s) ;
}
}
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> </ dependency>
package com. lagou. controller ;
import org. springframework. web. bind. annotation. RequestMapping ;
import org. springframework. web. bind. annotation. RestController ;
@RestController
@RequestMapping ( "hello" )
public class HelloController {
@RequestMapping ( "/boot" )
public String helloBoot ( ) {
return "Hello Spring Boot 哈哈哈" ;
}
}
#修改tomcat的端口号（有些时候也可以说是版本号）
server.port=8888
#定义数据库的连接信息 JdbcTemplate
#mysql-connector-java中5的版本就不加cj，6的版本需要加（高的版本一般也要加）
#这里是6.0.6的版本，所以需要加，因为版本不同，类结构可能也是不同的，不加的话
#可能会报错，但一般是可以兼容的，但也只是对高版本来说，即高版本可以加cj，也可以不加
#但低版本不能加cj，否则一般启动时会报错（初始化报错）
#启动一般说明的是：启动启动类报错（直接停止，需要重新启动了）
#若你是高版本，那么可以不用改变，但为了以防万一，最好修改）
#由于这是全局配置，spring boot在操作对应的数据库信息时
#自动配置的依赖操作数据库信息，比如jdbc依赖和mybatis依赖，只要是需要数据库信息的，就有这里的解释
#即会使用下面这些参数当成对应数据库信息的参数
#然后自动配置，若没有，则一般使用默认的值（只有用户名和密码有默认值，前面两个必须写，否则一般会报错）
#这个报错会使得访问不了，即后面的springmvc的操作停止，相当于没有自动配置了
#注意：
#spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#后面不能有空格，否则报错，这是一个特殊的地方，当然可以不写，会根据驱动默认加上的（这一般是spring boot自身的处理，其他的如单纯的spring可能还是需要指定）
#其他的基本都可以有空格（且空格无影响，相当于没有什么，基本不会参与到数值里面去）
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/lagou
spring.datasource.username=root
spring.datasource.password=123456
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> </ dependency> package com. lagou. controller ;
import org. springframework. beans. factory. annotation. Autowired ;
import org. springframework. jdbc. core. JdbcTemplate ;
import org. springframework. web. bind. annotation. RequestMapping ;
import org. springframework. web. bind. annotation. RestController ;
@RestController
@RequestMapping ( "hello" )
public class HelloController {
@RequestMapping ( "/boot" )
public String helloBoot ( ) {
return "Hello Spring Boot 哈哈哈" ;
}
@Autowired
private JdbcTemplate jdbcTemplate;
@RequestMapping ( "/jdbc" )
public String jdbc ( ) {
return jdbcTemplate. toString ( ) ;
}
}
package com. lagou. pojo ;
public class Pet {
private String type;
private String name;
@Override
public String toString ( ) {
return "Pet{" +
"type='" + type + '\'' +
", name='" + name + '\'' +
'}' ;
}
public String getType ( ) {
return type;
}
public void setType ( String type) {
this . type = type;
}
public String getName ( ) {
return name;
}
public void setName ( String name) {
this . name = name;
}
}
package com. lagou. pojo ;
import org. springframework. boot. context. properties. ConfigurationProperties ;
import org. springframework. stereotype. Component ;
import java. util. Arrays ;
import java. util. List ;
import java. util. Map ;
@Component
@ConfigurationProperties ( prefix = "person" )
public class Person {
private int id;
private String name;
private List hobby;
private String [ ] family;
private Map map;
private Pet pet;
@Override
public String toString ( ) {
return "Person{" +
"id=" + id +
", name='" + name + '\'' +
", hobby=" + hobby +
", family=" + Arrays . toString ( family) +
", map=" + map +
", pet=" + pet +
'}' ;
}
public int getId ( ) {
return id;
}
public void setId ( int id) {
this . id = id;
}
public String getName ( ) {
return name;
}
public void setName ( String name) {
this . name = name;
}
public List getHobby ( ) {
return hobby;
}
public void setHobby ( List hobby) {
this . hobby = hobby;
}
public String [ ] getFamily ( ) {
return family;
}
public void setFamily ( String [ ] family) {
this . family = family;
}
public Map getMap ( ) {
return map;
}
public void setMap ( Map map) {
this . map = map;
}
public Pet getPet ( ) {
return pet;
}
public void setPet ( Pet pet) {
this . pet = pet;
}
}
#自定义配置信息注入到Person对象中
person.id=100
person.name=哈哈
#list
person.hobby=喝水,吃早餐
#String[]
person.family=儿子,老婆
#集合和对象，一般都需要多一个层（多了.）
#Map
person.map.k1=v1
person.map.k2=v2
#Pet对象
person.pet.type=狗
person.pet.name=旺财
#他们可以使用@Value注解来进行注入（对应的参数获取），因为他们是全局的
@Autowired
private Person person;
@Test
public void configurationTest ( ) {
System . out. println ( person) ;
}
@Autowired
private Person person;
@RequestMapping ( "person" )
public String showPerson ( ) {
return person. toString ( ) ;
}
#解决中文乱码
#server.tomcat.uri-encoding=UTF-8
#spring.http.encoding.force=true
#spring.http.encoding.charset=UTF-8
#spring.http.encoding.enabled=true
#上面spring boot版本高的一般不能操作，与如下的作用基本类似
#一般是如下
#解决中文乱码
#tomcat编码，得到的请求数据以下面的编码格式进行操作，一般浏览器可以操作中文，（所以可以不用设置）
#如操作请求过来的参数，但也有可能url出现乱码，一般是js的操作，到那时一般需要使用encodeURI来进行传输
server.tomcat.uri-encoding=UTF-8
#对请求或者响应的编码设置（使得数据被操作），一般是解决post的，操作过滤
#因为不操作过滤，那么已经变化了，再次设置编码就并没有作用了（如springmvc就需要过滤，而不是去方法里面设置编码）
server.servlet.encoding.force=true
server.servlet.encoding.charset=UTF-8
server.servlet.encoding.enabled=true
< includes> < include> </ include> < include> </ include> < include> </ include> </ includes> server :
port : 8080
servlet :
context-path : /hello
person :
hobby :
- play
- read
- sleep
person :
hobby :
- play
- read
- sleep
person :
hobby :
- play
- read
- sleep
person :
hobby :
- play
- read
- sleep
person :
hobby :
- play
- read
- sleep
person :
hobby :
play,
read,
sleep
person :
hobby :
play,
read,
sleep
person :
hobby : [ play, read, sleep]
person :
hobby : play, read, sleep
person :
hobby :
play,
read,
sleep
person :
map :
k1 : v1
k2 : v2
person :
map : { k1 : v1, k2 : v2}
person :
id : 1
name : 王二麻子
family :
- 妻
- 妾
hobby :
- play
- read
- sleep
map :
k1 : value1
k2 : value2
pet :
type : 狗
name : 哈士奇
@Value ( "${person.id}" )
private int id;
package com. lagou. pojo ;
import org. springframework. beans. factory. annotation. Value ;
import org. springframework. stereotype. Component ;
@Component
public class Student {
@Value ( "${person.id}" )
private int id;
@Value ( "${person.name}" )
private String name;
@Override
public String toString ( ) {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
'}' ;
}
}
@Autowired
private Student student;
@Test public void studentTest ( ) {
System . out. println ( student) ;
}
#对实体类对象MyProperties进行属性配置
test.id=110
test.name=test
package com. lagou. pojo ;
import org. springframework. boot. context. properties. ConfigurationProperties ;
import org. springframework. context. annotation. PropertySource ;
import org. springframework. stereotype. Component ;
@Component
@PropertySource ( "classpath:test.properties" )
@ConfigurationProperties ( prefix = "test" )
public class MyProperties {
private int id;
private String name;
@Override
public String toString ( ) {
return "MyProperties{" +
"id=" + id +
", name='" + name + '\'' +
'}' ;
}
public int getId ( ) {
return id;
}
public void setId ( int id) {
this . id = id;
}
public String getName ( ) {
return name;
}
public void setName ( String name) {
this . name = name;
}
}
@Autowired
private MyProperties myProperties;
@Test
public void myPropertiesTest ( ) {
System . out. println ( myProperties) ;
}
对实体类对象MyProperties进行属性配置
test.id=110
test.name=test
package com. lagou. config ;
import com. lagou. service. MyService ;
import org. springframework. context. annotation. Bean ;
import org. springframework. context. annotation. Configuration ;
@Configuration
public class MyConfig {
@Bean
public MyService myService ( ) {
return new MyService ( ) ;
}
}
@Autowired
private MyService myService;
@Autowired
private MyConfig myConfig;
@Test
public void iocTest ( ) {
System . out. println ( myService) ;
System . out. println ( myConfig) ;
}
@Autowired
private ApplicationContext applicationContext;
@Test
public void Test ( ) {
System . out. println ( applicationContext. getBean ( "myService2" ) ) ;
System . out. println ( applicationContext. containsBean ( "myService2" ) ) ;
}
< parent> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < relativePath/> </ parent>
< parent> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> </ parent> < properties> < activemq.version> </ activemq.version> < antlr2.version> </ antlr2.version> < dependencies> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < scope> </ scope> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < scope> </ scope> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < scope> </ scope> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < scope> </ scope> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < scope> </ scope> </ dependency> </ dependencies> package com. lagou ;
import org. springframework. boot. SpringApplication ;
import org. springframework. boot. autoconfigure. SpringBootApplication ;
@SpringBootApplication
public class Springbootdome2Application {
public static void main ( String [ ] args) {
SpringApplication . run ( Springbootdome2Application . class , args) ;
}
}
@Target ( { ElementType . TYPE } )
@Retention ( RetentionPolicy . RUNTIME )
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan (
excludeFilters = { @Filter (
type = FilterType . CUSTOM ,
classes = { TypeExcludeFilter . class }
) , @Filter (
type = FilterType . CUSTOM ,
classes = { AutoConfigurationExcludeFilter . class }
) }
)
public @interface SpringBootApplication {
@AliasFor (
annotation = EnableAutoConfiguration . class
)
Class < ? > [ ] exclude ( ) default { } ;
@AliasFor (
annotation = EnableAutoConfiguration . class
)
String [ ] excludeName ( ) default { } ;
@AliasFor (
annotation = ComponentScan . class ,
attribute = "basePackages"
)
String [ ] scanBasePackages ( ) default { } ;
@AliasFor (
annotation = ComponentScan . class ,
attribute = "basePackageClasses"
)
Class < ? > [ ] scanBasePackageClasses ( ) default { } ;
@AliasFor (
annotation = ComponentScan . class ,
attribute = "nameGenerator"
)
Class < ? extends BeanNameGenerator > nameGenerator ( ) default BeanNameGenerator . class ;
@AliasFor (
annotation = Configuration . class
)
boolean proxyBeanMethods ( ) default true ;
}
@Target ( { ElementType . TYPE } )
@Retention ( RetentionPolicy . RUNTIME )
@Documented
@Configuration
@Indexed
public @interface SpringBootConfiguration {
@AliasFor (
annotation = Configuration . class
)
boolean proxyBeanMethods ( ) default true ;
}
@Target ( { ElementType . TYPE } )
@Retention ( RetentionPolicy . RUNTIME )
@Documented
@Inherited
@AutoConfigurationPackage
@Import ( { AutoConfigurationImportSelector . class } )
public @interface EnableAutoConfiguration {
String ENABLED_OVERRIDE_PROPERTY = "spring.boot.enableautoconfiguration" ;
Class < ? > [ ] exclude ( ) default { } ;
String [ ] excludeName ( ) default { } ;
}
@Target ( { ElementType . TYPE } )
@Retention ( RetentionPolicy . RUNTIME )
@Documented
@Inherited
@Import ( { Registrar . class } )
public @interface AutoConfigurationPackage {
String [ ] basePackages ( ) default { } ;
Class < ? > [ ] basePackageClasses ( ) default { } ;
}
static class Registrar implements ImportBeanDefinitionRegistrar , DeterminableImports {
Registrar ( ) {
}
public void registerBeanDefinitions ( AnnotationMetadata metadata, BeanDefinitionRegistry
registry) {
AutoConfigurationPackages . register ( registry, ( String [ ] ) (
new AutoConfigurationPackages. PackageImports ( metadata) ) .
getPackageNames ( ) . toArray ( new String [ 0 ] ) ) ;
}
public Set < Object > determineImports ( AnnotationMetadata metadata) {
return Collections . singleton ( new AutoConfigurationPackages. PackageImports ( metadata) ) ;
}
}
public String [ ] selectImports ( AnnotationMetadata annotationMetadata) {
if ( ! this . isEnabled ( annotationMetadata) ) {
return NO_IMPORTS ;
} else {
AutoConfigurationImportSelector. AutoConfigurationEntry autoConfigurationEntry =
this . getAutoConfigurationEntry ( annotationMetadata) ;
return StringUtils . toStringArray ( autoConfigurationEntry. getConfigurations ( ) ) ;
}
}
this . autoConfigurationMetadata = AutoConfigurationMetadataLoader . loadMetadata ( this . beanClassLoader) ;
static AutoConfigurationMetadata loadMetadata ( ClassLoader classLoader) {
return loadMetadata ( classLoader, "META-INF/spring-autoconfigure-metadata.properties" ) ;
}
static AutoConfigurationMetadata loadMetadata ( ClassLoader classLoader, String path) {
try {
Enumeration < URL> = classLoader !=
null ? classLoader. getResources ( path) : ClassLoader . getSystemResources ( path) ;
Properties properties = new Properties ( ) ;
while ( urls. hasMoreElements ( ) ) {
properties. putAll ( PropertiesLoaderUtils . loadProperties (
new UrlResource ( ( URL ) urls. nextElement ( ) ) ) ) ;
}
return loadMetadata ( properties) ;
} catch ( IOException var4) {
throw new IllegalArgumentException ( "Unable to load @ConditionalOnClass location ["
+ path + "]" , var4) ;
}
}
static AutoConfigurationMetadata loadMetadata ( Properties properties) {
return new AutoConfigurationMetadataLoader. PropertiesAutoConfigurationMetadata ( properties) ;
}
org.springframework.boot.autoconfigure.amqp.RabbitAnnotationDrivenConfiguration.ConditionalOnClass=
org.springframework.amqp.rabbit.annotation.EnableRabbit
#其中org.springframework.boot.autoconfigure.amqp.RabbitAnnotationDrivenConfiguration
#第一个点，往前推
#代表进行自动配置的类，后面的ConditionalOnClass是一个注解，该注解一般表示的是条件（=后面的）
#如果要向ioc容器中注入我们自动配置的类需要满足=号后面的条件
#具体条件（条件有很多种，不同的注解是不同的意思，比如@ConditionalOnBean：判断某个特定的 bean 是否存在，如果存在，则注册当前的 bean）是
#当该注解里面出现了后面的org.springframework.amqp.rabbit.annotation.EnableRabbit（EnableRabbit这个类时，因为约定，所以存在某个地方统一获取的）
#就进行该RabbitAnnotationDrivenConfiguration类的自动注入
#自动注入：可以说成是自动的创建实例，放在ioc容器里面（注意：通常只是放入列表中，具体由spring初始化完成）
#即使得可以被注入得到，所以我们导入对应的依赖，spring boot会帮我们生成实例，就是这样的原因，但并不是所有依赖，因为该文件的内容是有限的，这是肯定的
#其他的基本都是这样的说明
#无论是自动配置还是扫描，都是单纯的操作注册（前面或者后面的内容可能说自动配置操作了创建实例，只是结合了总体来说而已，具体只要spring没有初始化，都只是保存对应的包信息，也就是注册，所以后面或者前面说明放入ioc容器本质是结合总体来说的，需要注意这一点）
protected AutoConfigurationImportSelector. AutoConfigurationEntry
getAutoConfigurationEntry ( AnnotationMetadata annotationMetadata) {
if ( ! this . isEnabled ( annotationMetadata) ) {
return EMPTY_ENTRY ;
} else {
AnnotationAttributes attributes = this . getAttributes ( annotationMetadata) ;
List < String > = this . getCandidateConfigurations ( annotationMetadata,
attributes) ;
configurations = this . removeDuplicates ( configurations) ;
Set < String > = this . getExclusions ( annotationMetadata, attributes) ;
this . checkExcludedClasses ( configurations, exclusions) ;
configurations. removeAll ( exclusions) ;
configurations = this . getConfigurationClassFilter ( ) . filter ( configurations) ;
this . fireAutoConfigurationImportEvents ( configurations, exclusions) ;
return new AutoConfigurationImportSelector. AutoConfigurationEntry ( configurations,
exclusions) ;
}
}
protected List < String > getCandidateConfigurations ( AnnotationMetadata metadata, AnnotationAttributes
attributes) {
List < String > =
new ArrayList ( SpringFactoriesLoader . loadFactoryNames (
this . getSpringFactoriesLoaderFactoryClass ( ) , this . getBeanClassLoader ( ) ) ) ;
ImportCandidates . load ( AutoConfiguration . class ,
this . getBeanClassLoader ( ) ) . forEach ( configurations:: add ) ;
Assert . notEmpty ( configurations, "No auto configuration classes found in META -
INF / spring. factories nor in META -
INF / spring/ org. springframework. boot. autoconfigure. AutoConfiguration. imports.
If you are using a custom packaging, make sure that file is correct. ") ;
return configurations;
}
protected Class < ? > getSpringFactoriesLoaderFactoryClass ( ) {
return EnableAutoConfiguration . class ;
}
protected ClassLoader getBeanClassLoader ( ) {
return this . beanClassLoader;
}
public static List < String > loadFactoryNames ( Class < ? > , @Nullable ClassLoader classLoader)
{
ClassLoader classLoaderToUse = classLoader;
if ( classLoader == null ) {
classLoaderToUse = SpringFactoriesLoader . class . getClassLoader ( ) ;
}
String factoryTypeName = factoryType. getName ( ) ;
return ( List ) loadSpringFactories ( classLoaderToUse) . getOrDefault ( factoryTypeName,
Collections . emptyList ( ) ) ;
}
private static Map < String , List < String > > loadSpringFactories ( ClassLoader classLoader) {
Map < String , List < String > > = ( Map ) cache. get ( classLoader) ;
if ( result != null ) {
return result;
} else {
HashMap result = new HashMap ( ) ;
try {
Enumeration urls = classLoader. getResources ( "META-INF/spring.factories" ) ;
while ( urls. hasMoreElements ( ) ) {
URL url = ( URL ) urls. nextElement ( ) ;
UrlResource resource = new UrlResource ( url) ;
Properties properties = PropertiesLoaderUtils . loadProperties ( resource) ;
Iterator var6 = properties. entrySet ( ) . iterator ( ) ;
while ( var6. hasNext ( ) ) {
Entry < ? , ? > = ( Entry ) var6. next ( ) ;
String factoryTypeName = ( ( String ) entry. getKey ( ) ) . trim ( ) ;
String [ ] factoryImplementationNames =
StringUtils . commaDelimitedListToStringArray ( ( String ) entry. getValue ( ) ) ;
String [ ] var10 = factoryImplementationNames;
int var11 = factoryImplementationNames. length;
for ( int var12 = 0 ; var12 < var11; ++ var12) {
String factoryImplementationName = var10[ var12] ;
( ( List ) result. computeIfAbsent ( factoryTypeName, ( key) -> {
return new ArrayList ( ) ;
} ) ) . add ( factoryImplementationName. trim ( ) ) ;
}
}
}
result. replaceAll ( ( factoryType, implementations) -> {
return ( List ) implementations. stream ( ) . distinct ( ) . collect (
Collectors . collectingAndThen ( Collectors . toList ( ) ,
Collections :: unmodifiableList ) ) ;
} ) ;
cache. put ( classLoader, result) ;
return result;
} catch ( IOException var14) {
throw new IllegalArgumentException ( "Unable to load factories from location [ META -
INF / spring. factories] ", var14) ;
}
}
}
public final class SpringFactoriesLoader {
public static final String FACTORIES_RESOURCE_LOCATION = "META-INF/spring.factories" ;
@Import ( { Registrar . class } )
@Import ( { AutoConfigurationImportSelector . class } )
CREATE DATABASE springbootdata;
USE springbootdata;
DROP TABLE IF EXISTS t_article;
CREATE TABLE t_article (
id int ( 20 ) NOT NULL AUTO_INCREMENT COMMENT '文章id' ,
title varchar ( 200 ) DEFAULT NULL COMMENT '文章标题' ,
content longtext COMMENT '文章内容' ,
PRIMARY KEY ( id)
) ENGINE = InnoDB AUTO_INCREMENT = 2 DEFAULT CHARSET = utf8;
INSERT INTO t_article VALUES ( '1' , 'Spring Boot基础入门' , '从入门到精通讲解...' ) ;
INSERT INTO t_article VALUES ( '2' , 'Spring Cloud基础入门' , '从入门到精通讲解...' ) ;
DROP TABLE IF EXISTS t_comment;
CREATE TABLE t_comment (
id int ( 20 ) NOT NULL AUTO_INCREMENT COMMENT '评论id' ,
content longtext COMMENT '评论内容' ,
author varchar ( 200 ) DEFAULT NULL COMMENT '评论作者' ,
a_id int ( 20 ) DEFAULT NULL COMMENT '关联的文章id' ,
PRIMARY KEY ( id)
) ENGINE = InnoDB AUTO_INCREMENT = 3 DEFAULT CHARSET = utf8;
INSERT INTO t_comment VALUES ( '1' , '很全、很详细' , 'lucy' , '1' ) ;
INSERT INTO t_comment VALUES ( '2' , '赞一个' , 'tom' , '1' ) ;
INSERT INTO t_comment VALUES ( '3' , '很详细' , 'eric' , '1' ) ;
INSERT INTO t_comment VALUES ( '4' , '很好，非常详细' , '张三' , '1' ) ;
INSERT INTO t_comment VALUES ( '5' , '很不错' , '李四' , '2' ) ;
<?xml version="1.0" encoding="UTF-8"?>
< projectxmlns = " http://maven.apache.org/POM/4.0.0" xmlns: xsi= " http://www.w3.org/2001/XMLSchema-
instance" xsi: schemaLocation= " http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-
4.0.0.xsd" > < modelVersion> </ modelVersion> < parent> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < relativePath/> </ parent> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < name> </ name> < description> </ description> < properties> < java.version> </ java.version> </ properties> < dependencies> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < scope> </ scope> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> < scope> </ scope> </ dependency> </ dependencies> < build> < plugins> < plugin> < groupId> </ groupId> < artifactId> </ artifactId> </ plugin> </ plugins> </ build> </ project>
Comment类：
package com. lagou. bootmybatis. pojo ;
public class Comment {
private Integer id;
private String content;
private String author;
private Integer aId;
@Override
public String toString ( ) {
return "Comment{" +
"id=" + id +
", content='" + content + '\'' +
", author='" + author + '\'' +
", aId=" + aId +
'}' ;
}
public Integer getId ( ) {
return id;
}
public void setId ( Integer id) {
this . id = id;
}
public String getContent ( ) {
return content;
}
public void setContent ( String content) {
this . content = content;
}
public String getAuthor ( ) {
return author;
}
public void setAuthor ( String author) {
this . author = author;
}
public Integer getaId ( ) {
return aId;
}
public void setaId ( Integer aId) {
this . aId = aId;
}
}
package com. lagou. bootmybatis. pojo ;
public class Article {
private Integer id;
private String title;
private String content;
@Override
public String toString ( ) {
return "Article{" +
"id=" + id +
", title='" + title + '\'' +
", content='" + content + '\'' +
'}' ;
}
public Integer getId ( ) {
return id;
}
public void setId ( Integer id) {
this . id = id;
}
public String getTitle ( ) {
return title;
}
public void setTitle ( String title) {
this . title = title;
}
public String getContent ( ) {
return content;
}
public void setContent ( String content) {
this . content = content;
}
}
spring :
datasource :
url : jdbc: mysql: //localhost: 3306/springbootdata? serverTimezone=UTC&characterEncoding=UTF- 8
username : root
password : 123456
需求：实现通过ID查询Comment信息
创建一个对t_comment表数据操作的接口CommentMapper
package com. lagou. bootmybatis. mapper ;
import com. lagou. bootmybatis. pojo. Comment ;
import org. apache. ibatis. annotations. Select ;
public interface CommentMapper {
@Select ( "select * from t_comment where id = #{id}" )
public Comment findById ( Integer id) ;
}
package com. lagou. bootmybatis ;
import org. mybatis. spring. annotation. MapperScan ;
import org. springframework. boot. SpringApplication ;
import org. springframework. boot. autoconfigure. SpringBootApplication ;
@SpringBootApplication
@MapperScan ( "com.lagou.bootmybatis.mapper" )
public class BootmybatisApplication {
public static void main ( String [ ] args) {
SpringApplication . run ( BootmybatisApplication . class , args) ;
}
}
package com. lagou. bootmybatis ;
import com. lagou. bootmybatis. mapper. CommentMapper ;
import com. lagou. bootmybatis. pojo. Comment ;
import org. junit. jupiter. api. Test ;
import org. junit. runner. RunWith ;
import org. springframework. beans. factory. annotation. Autowired ;
import org. springframework. boot. test. context. SpringBootTest ;
import org. springframework. test. context. junit4. SpringRunner ;
@RunWith ( SpringRunner . class )
@SpringBootTest
class BootmybatisApplicationTests {
@Autowired
private CommentMapper commentMapper;
@Test
void contextLoads ( ) {
Comment byId = commentMapper. findById ( 1 ) ;
System . out. println ( byId) ;
}
}
因为这时控制台中查询的Comment的aId属性值为null，没有映射成功
这是因为编写的实体类Comment中使用了驼峰命名方式将t_comment表中的a_id字段设计成了aId属性，所以无法正确映射查询结果了
mybatis :
configuration :
map-underscore-to-camel-case : true
package com. lagou. bootmybatis. mapper ;
import com. lagou. bootmybatis. pojo. Article ;
import org. apache. ibatis. annotations. Mapper ;
@Mapper
public interface ArticleMapper {
public Article selectArticle ( Integer id) ;
}
<?xml version="1.0" encoding="UTF-8" ?>
<! DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd" > < mappernamespace = " com.lagou.mapper.ArticleMapper" > < selectid = " selectArticle" resultType = " Article" > </ select> </ mapper>
mybatis :
configuration :
map-underscore-to-camel-case : true
mapper-locations : classpath: mapper/*.xml
type-aliases-package : com.lagou.bootmybatis.pojo
mybatis :
configuration :
map-underscore-to-camel-case : true
mapper-locations : classpath: mapper/*.xml
type-aliases-package : com.lagou.bootmybatis.pojo
mybatis :
configuration :
map-underscore-to-camel-case : true
mapper-locations : classpath: mapper/*.xml
type-aliases-package : com.lagou.bootmybatis.pojo
@Autowired
private ArticleMapper articleMapper;
@Test
void findArticleMapperById ( ) {
Article article = articleMapper. selectByPrimaryKey ( 1 ) ;
System . out. println ( article) ;
}
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> </ dependency>
spring :
datasource :
url : jdbc: mysql: //localhost: 3306/springbootdata? serverTimezone=UTC&characterEncoding=UTF- 8
username : root
password : 123456
redis :
host : 192.168.164.128
port : 6379
mybatis :
configuration :
map-underscore-to-camel-case : true
mapper-locations : classpath: mapper/*.xml
type-aliases-package : com.lagou.bootmybatis.pojo
package com. lagou. bootmybatis. util ;
import org. springframework. beans. factory. annotation. Autowired ;
import org. springframework. data. redis. core. RedisTemplate ;
import org. springframework. stereotype. Component ;
import java. util. concurrent. TimeUnit ;
@Component
public class RedisUtils {
@Autowired
private RedisTemplate redisTemplate;
public Object get ( final String key) {
return redisTemplate. opsForValue ( ) . get ( key) ;
}
public boolean set ( String key, Object value) {
boolean result = false ;
try {
redisTemplate. opsForValue ( ) . set ( key, value, 1 , TimeUnit . DAYS ) ;
result = true ;
} catch ( Exception e) {
e. printStackTrace ( ) ;
}
return result;
}
public boolean getAndSet ( final String key, String value) {
boolean result = false ;
try {
redisTemplate. opsForValue ( ) . getAndSet ( key, value) ;
result = true ;
} catch ( Exception e) {
e. printStackTrace ( ) ;
}
return result;
}
public boolean delete ( final String key) {
boolean result = false ;
try {
redisTemplate. delete ( key) ;
result = true ;
} catch ( Exception e) {
e. printStackTrace ( ) ;
}
return result;
}
}
package com. lagou. bootmybatis ;
import com. lagou. bootmybatis. mapper. ArticleMapper ;
import com. lagou. bootmybatis. mapper. CommentMapper ;
import com. lagou. bootmybatis. pojo. Article ;
import com. lagou. bootmybatis. pojo. Comment ;
import com. lagou. bootmybatis. util. RedisUtils ;
import org. junit. jupiter. api. Test ;
import org. junit. runner. RunWith ;
import org. springframework. beans. factory. annotation. Autowired ;
import org. springframework. boot. test. context. SpringBootTest ;
import org. springframework. test. context. junit4. SpringRunner ;
import java. util. ArrayList ;
@RunWith ( SpringRunner . class )
@SpringBootTest
class BootmybatisApplicationTests {
@Autowired
private CommentMapper commentMapper;
@Test
void contextLoads ( ) {
Comment byId = commentMapper. findById ( 1 ) ;
System . out. println ( byId) ;
}
@Autowired
private ArticleMapper articleMapper;
@Test
void findArticleMapperById ( ) {
Article article = articleMapper. selectByPrimaryKey ( 1 ) ;
System . out. println ( article) ;
}
@Autowired
private RedisUtils redisUtils;
@Test
public void writeRedis ( ) {
boolean set = redisUtils. set ( "1" , articleMapper. selectByPrimaryKey ( 1 ) ) ;
System . out. println ( set) ;
}
@Test
public void readRedis ( ) {
Article article = ( Article ) redisUtils. get ( "1" ) ;
System . out. println ( article) ;
}
}
spring :
datasource :
url : jdbc: mysql: //localhost: 3306/springbootdata? serverTimezone=UTC&characterEncoding=UTF- 8
username : root
password : 123456
redis :
host : 192.168.164.128
port : 6379
jedis :
pool :
max-active : 18
max-wait : 3000
max-idle : 20
min-idle : 2
timeout : 3000
<! DOCTYPE html > < htmllang = " en" xmlns: th= " http://www.thymeleaf.org" > < head> < metacharset = " UTF-8" > < linkrel = " stylesheet" type = " text/css" media = " all" href = " ../../css/gtvg.css" th: href= " @{/css/gtvg.css}" /> < title> </ title> </ head> < body> < pth: text= " ${hello}" > </ p> </ body> </ html>
< pth: text= " ${title}" > </ p> Object title = model. getAttribute ( "title" ) ;
System . out. println ( title) ;
The locale country is: < spanth: text= " ${#locale.country}" > </ span> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> </ dependency> spring :
thymeleaf :
cache : true
encoding : UTF- 8
mode : HTML5
prefix : classpath: /templates/
suffix : .html
#若是properties的话，就是如下：
spring.thymeleaf.cache = true #启用模板缓存
spring.thymeleaf.encoding = UTF_8 #模板编码
spring.thymeleaf.mode = HTML5 #应用于模板的模板模式
spring.thymeleaf.prefix = classpath:/templates/ #指定模板页面存放路径
spring.thymeleaf.suffix = .html #指定模板页面名称的后缀
#实际上不难发现，对应的层级都是一层一层的，properties使用.代表层级，yaml（yml)使用":以及对应的级别"代表层级
#只是表达方式的差异而已，作用还是一样的
function sum ( a, b ) {
return a+ b;
}
spring :
thymeleaf :
cache : false
encoding : UTF- 8
mode : HTML5
prefix : classpath: /templates/
suffix : .html
package com. lagou. thymeleaf. controller ;
import org. springframework. stereotype. Controller ;
import org. springframework. ui. Model ;
import org. springframework. web. bind. annotation. RequestMapping ;
import java. util. Calendar ;
@Controller
public class LoginController {
@RequestMapping ( "/toLoginPage" )
public String toLoginPage ( Model model) {
model. addAttribute ( "currentYear" , Calendar . getInstance ( ) . get ( Calendar . YEAR ) ) ;
return "login" ;
}
}
<! DOCTYPE html > < htmllang = " en" xmlns: th= " http://www.thymeleaf.org" > < head> < metacharset = " UTF-8" > < linkrel = " stylesheet" type = " text/css" media = " all" href = " ../../css/gtvg.css" th: href= " @{/css/gtvg.css}" /> < title> </ title> </ head> < body> < spanth: text= " ${#locale.country}" > </ span> < br> < spanth: text= " ${#locale.language}" > </ span> < br> < spanth: text= " ${currentYear}" > </ span> < br> < spanth: text= " ${currentYearr}" > </ span> < br> </ body> </ html>
< divth: object= " ${book}" > < p> < spanth: text= " *{title}" > </ span> </ p> </ div> package com. lagou. thymeleaf. pojo ;
public class book {
private String title;
public book ( ) {
}
public book ( String title) {
this . title = title;
}
@Override
public String toString ( ) {
return "book{" +
"title='" + title + '\'' +
'}' ;
}
public String getTitle ( ) {
return title;
}
public void setTitle ( String title) {
this . title = title;
}
}
model. addAttribute ( "book" , new book ( "111" ) ) ;
spring :
thymeleaf :
cache : false
encoding : UTF- 8
mode : HTML5
prefix : classpath: /templates/
suffix : .html
messages :
basename : message
home.tv=哈哈哈
home.tv=哦哦哦
home.tv=嘿嘿嘿
< spanth: text= " #{home.tv}" > </ span> < ath: href= " @{http://localhost:8080/order/details(orderId=${o.id})}" > </ a> < ath: href= " @{/order/details(orderId=${o.id},pid=${p.id})}" > </ a> < ath: href= " @{http://www.baidu.com}" > </ a> < divth: insert= " ~{thymeleafDemo::title}" > </ div> <! DOCTYPE html > < htmllang = " en" xmlns: th= " http://www.thymeleaf.org" > < head> < metacharset = " UTF-8" > < title> </ title> </ head> < body> < divth: fragment= " fa" > </ div> </ body> </ html> < divth: insert= " ~{index::fa}" > </ div> <! DOCTYPE html > < htmllang = " en" xmlns: th= " http://www.thymeleaf.org" > < head> < metahttp-equiv = " Content-Type" content = " text/html; charset=UTF-8" > < metaname = " viewport" content = " width=device-width, initial-scale=1,shrink-to-fit=no" > < title> </ title> < linkth: href= " @{/login/css/bootstrap.min.css}" rel = " stylesheet" > < linkth: href= " @{/login/css/signin.css}" rel = " stylesheet" > </ head> < bodyclass = " text-center" > < formclass = " form-signin" > < imgclass = " mb-4" th: src= " @{/login/img/login.jpg}" width = " 72" height = " 72" > < h1class = " h3 mb-3 font-weight-normal" > </ h1> < inputtype = " text" class = " form-control" th: placeholder= " 用户名" required = " " autofocus = " " > < inputtype = " password" class = " form-control" th: placeholder= " 密码" required = " " > < divclass = " checkbox mb-3" > < label> < inputtype = " checkbox" value = " remember-me" > </ label> </ div> < buttonclass = " btn btn-lg btn-primary btn-block" type = " submit" > </ button> < pclass = " mt-5 mb-3 text-muted" > < spanth: text= " ${currentYear}" > </ span> < spanth: text= " ${currentYear}+1" > </ span> </ p> </ form> </ body> </ html>
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> < scope> </ scope> </ dependency>
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> < optional> </ optional> </ dependency> package com. lagou. thy. bean ;
import lombok. Data ;
@Data
public class User {
private Integer id;
private String username;
private String password;
private String birthday;
private static final long serialVersionUID = 1L ;
}
package com. lagou. thy ;
import com. lagou. thy. bean. User ;
import org. junit. jupiter. api. Test ;
import org. springframework. boot. test. context. SpringBootTest ;
@SpringBootTest
class ThyApplicationTests {
@Test
void contextLoads ( ) {
User u = new User ( ) ;
u. setId ( 1 ) ;
u. setUsername ( "好好" ) ;
System . out. println ( u) ;
}
}
CREATE TABLE USER (
id INT ( 10 ) PRIMARY KEY AUTO_INCREMENT ,
username VARCHAR ( 20 ) ,
PASSWORD VARCHAR ( 20 ) ,
birthday VARCHAR ( 20 )
)
INSERT INTO USER VALUES ( 1 , 'zhangsan' , '123' , '2020-10-10' )
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> < version> </ version> </ dependency> < dependency> < groupId> </ groupId> < artifactId> </ artifactId> </ dependency> package com. lagou. thy ;
import org. mybatis. spring. annotation. MapperScan ;
import org. springframework. boot. SpringApplication ;
import org. springframework. boot. autoconfigure. SpringBootApplication ;
import org. springframework. context. annotation. ComponentScan ;
import org. springframework. stereotype. Component ;
@SpringBootApplication
@MapperScan ( "com.lagou" )
public class ThyApplication {
public static void main ( String [ ] args) {
SpringApplication . run ( ThyApplication . class , args) ;
}
}
server :
port : 8090
servlet :
context-path : /
spring :
datasource :
name : druid
type : com.alibaba.druid.pool.DruidDataSource
url : jdbc: mysql: //localhost: 3306/springbootdata? characterEncoding=utf- 8&serverTimezone=UTC
username : root
password : 123456
mybatis :
mapper-locations : classpath: mapper/*Dao.xml
package com. lagou. thy. service ;
import com. lagou. thy. bean. User ;
import java. util. List ;
public interface UserService {
List < User > queryAll ( ) ;
User findById ( Integer id) ;
void insert ( User user) ;
void deleteById ( Integer id) ;
void update ( User user) ;
}
List < User > queryAll ( ) ;
package com. lagou. thy. service. impl ;
import com. lagou. thy. bean. User ;
import com. lagou. thy. dao. UserDao ;
import com. lagou. thy. service. UserService ;
import org. springframework. beans. factory. annotation. Autowired ;
import org. springframework. stereotype. Service ;
import java. util. List ;
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserDao userDao;
@Override
public List < User > queryAll ( ) {
List < User > = userDao. queryAll ( ) ;
System . out. println ( 1 ) ;
return users;
}
@Override
public User findById ( Integer id) {
User user = userDao. selectByPrimaryKey ( id) ;
return user;
}
@Override
public void insert ( User user) {
userDao. insertSelective ( user) ;
}
@Override
public void deleteById ( Integer id) {
userDao. deleteByPrimaryKey ( id) ;
}
@Override
public void update ( User user) {
userDao. updateByPrimaryKeySelective ( user) ;
}
}
package com. lagou. thy. controller ;
import com. lagou. thy. bean. User ;
import com. lagou. thy. service. UserService ;
import org. springframework. beans. factory. annotation. Autowired ;
import org. springframework. web. bind. annotation. GetMapping ;
import org. springframework. web. bind. annotation. PathVariable ;
import org. springframework. web. bind. annotation. RequestMapping ;
import org. springframework. web. bind. annotation. RestController ;
import java. util. List ;
@RestController
@RequestMapping ( "/user" )
public class UserController {
@Autowired
private UserService userService;
@GetMapping ( "/query" )
public List < User > queryAll ( ) {
List < User > = userService. queryAll ( ) ;
return users;
}
@GetMapping ( "/query/{id}" )
public User queryById ( @PathVariable Integer id) {
return userService. findById ( id) ;
}
@DeleteMapping ( "/delete/{id}" )
public String delete ( @PathVariable Integer id) {
userService. deleteById ( id) ;
return "删除成功" ;
}
@PostMapping ( "insert" )
public String insert ( User user) {
userService. insert ( user) ;
return "新增成功" ;
}
@PutMapping ( "/update" )
public String update ( User user) {
userService. update ( user) ;
return "修改成功" ;
}
}
< build> < plugins> < plugin> < groupId> </ groupId> < artifactId> </ artifactId> </ plugin> </ plugins> </ build>
< dependency> < groupId> </ groupId> < artifactId> </ artifactId> </ dependency>
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