学习目标:
需求分析与SSM环境准备(上)
学习二分搜索树删除最大元素与最小元素
学习内容:
Spring与SpringMVC环境准备,解决请求与响应乱码问题,完成Spring与Mybatis的整合,继承Junit单元测试与Logback日志。代码如下:
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="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>4.0.0</modelVersion>
<groupId>org.example</groupId>
<artifactId>imooc-reader</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<repositories>
<repository>
<id>aliyun</id>
<name>aliyun</name>
<url>https://maven.aliyun.com/repository/public</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.3.8</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.12.3</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.3.8</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.6</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.27</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.2.13-SNSAPSHOT</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>5.3.8</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.2.3</version>
</dependency>
</dependencies>
</project>
applicationContext.xml:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/task
http://www.springframework.org/schema/task/spring-task.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.imooc"/>
<mvc:annotation-driven>
<mvc:message-converters>
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>application/json;charset=utf-8</value>
</list>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
<mvc:default-servlet-handler/>
<!-- MyBatis与Spring的整合配置-->
<!-- 1.配置数据源-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/imooc_reader?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true"/>
<property name="username" value="root"/>
<property name="password" value="zjh123"/>
<property name="initialSize" value="5"/>
<property name="maxActive" value="20"/>
</bean>
<!-- 2.配置Session与FactoryBean-->
<bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="mapperLocations" value="classpath:mappers/*.xml"/>
<property name="configLocation" value="classpath:mybatis-config.xml"/>
</bean>
<!-- 3.配置Mapper扫描器-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.imooc.reader.mapper"/>
</bean>
</beans>
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>spring-mvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext*.xml</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring-mvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<filter>
<filter-name>characterFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>characterFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
mybatis-config.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<settings>
<setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>
</configuration>
logback.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<configuration>
<appender name="console" class="ch.qos.logback.core.ConsoleAppender">
<encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
<pattern>[%thread] %d %level %logger{10} -%msg%n</pattern>
<charset>UTF-8</charset>
</encoder>
</appender>
<!-- <appender name="accessHistoryLog" class="ch.qos.logback.core.rolling.RollingFileAppender">-->
<!-- <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">-->
<!-- <fileNamePattern>d:/logs/history.%d.log</fileNamePattern>-->
<!-- </rollingPolicy>-->
<!-- <encoder>-->
<!-- <pattern>[%thread] %d %level %logger{10} -%msg%n</pattern>-->
<!-- </encoder>-->
<!-- </appender>-->
<root level="debug">
<appender-ref ref="console"/>
</root>
<!-- <logger name="com.imooc.restful.interceptor.AccessHistoryInterceptor" level="INFO" additivity="false">-->
<!-- <appender-ref ref="accessHistoryLog"/>-->
<!-- </logger>-->
</configuration>
二分搜索树:
import com.sun.corba.se.impl.resolver.SplitLocalResolverImpl;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;
public class BST<E extends Comparable<E>> {
private class Node {
public E e;
public Node left, right;
public Node(E e) {
this.e = e;
left = null;
right = null;
}
}
private Node root;
private int size;
public BST() {
root = null;
size = 0;
}
public int size() {
return size;
}
public boolean isEmpty() {
return size == 0;
}
//向二分搜索树中添加新的元素e
public void add(E e) {
root = add(root, e);
}
//向以node为根的二分搜索树中插入元素E,递归算法
//返回插入节点后二分搜索树的根
private Node add(Node node, E e) {
if (node == null) {
size++;
return new Node(e);
}
if (e.compareTo(node.e) < 0) {
node.left = add(node.left, e);
} else if (e.compareTo(node.e) > 0)
node.right = add(node.right, e);
return node;
}
//看二分搜索树中是否包含元素e
public boolean contains(E e) {
return contains(root, e);
}
//以node为根的二分搜索树中是否包含元素e,递归算法
private boolean contains(Node node, E e) {
if (node == null)
return false;
if (e.compareTo(node.e) == 0)
return true;
else if (e.compareTo(node.e) < 0)
return contains(node.left, e);
else
return contains(node.right, e);
}
//二分搜索树的前序遍历
public void preOrder() {
preOrder(root);
}
//前序遍历以node为根的二分搜索树,递归算法
private void preOrder(Node node) {
if (node == null)
return;
System.out.println(node.e);
preOrder(node.left);
preOrder(node.right);
}
//二分搜索树的非递归前序遍历
public void preOrderNR() {
Stack<Node> stack = new Stack<>();
stack.push(root);
while (!stack.isEmpty()){
Node cur = stack.pop();
System.out.println(cur.e);
if(cur.right!=null)
stack.push(cur.right);
if (cur.left != null)
stack.push(cur.left);
}
}
//二分搜索树的中序遍历
public void inOrder() {
inOrder(root);
}
//中序遍历以node为根的二分搜索树,递归算法
private void inOrder(Node node) {
if (node == null) {
return;
}
inOrder(node.left);
System.out.println(node.e);
inOrder(node.right);
}
//二分搜索树的后序遍历
public void postOrder() {
postOrder(root);
}
//后序遍历以node为根的二分搜索树,递归算法
private void postOrder(Node node){
if(node==null){
return;
}
postOrder(node.left);
postOrder(node.right);
System.out.println(node.e);
}
//二分搜索树的层序遍历
public void levelOrder(){
Queue<Node> q = new LinkedList<>();
q.add(root);
while (!q.isEmpty()) {
Node cur = q.remove();
System.out.println(cur.e);
if (cur.left != null)
q.add(cur.left);
if (cur.right != null)
q.add(cur.right);
}
}
//寻找二分搜索树的最小元素
public E minimum(){
if (size == 0)
throw new IllegalArgumentException("BST is empty!");
return minimum(root).e;
}
//返回以node为根的二分搜索树的最小值所在的节点
private Node minimum(Node node){
if(node.left==null)
return node;
return minimum(node.left);
}
//寻找二分搜索树的最大元素
public E maximum(){
if (size == 0)
throw new IllegalArgumentException("BST is empty!");
return maximum(root).e;
}
//返回以node为根的二分搜索树的最大值所在的节点
private Node maximum(Node node){
if(node.right==null)
return node;
return minimum(node.right);
}
//从二分搜索树中删除最小值所在的节点,返回最小值
public E removeMin(){
E ret = minimum();
root=removeMin(root);
return ret;
}
//删除掉以node为根的二分搜索树中的最小节点
//返回删除节点后新的二分搜索树的根
private Node removeMin(Node node){
if(node.left==null){
Node rightNode=node.right;
node.right=null;
size--;
return rightNode;
}
node.left = removeMin(node.left);
return node;
}
//从二分搜索树中删除最大值所在的节点,返回最小值
public E removeMax(){
E ret = maximum();
root=removeMax(root);
return ret;
}
//删除掉以node为根的二分搜索树中的最大节点
//返回删除节点后新的二分搜索树的根
private Node removeMax(Node node){
if(node.right==null){
Node leftNode=node.left;
node.left=null;
size--;
return leftNode;
}
node.right = removeMax(node.right);
return node;
}
@Override
public String toString() {
StringBuilder res = new StringBuilder();
generateBSTString(root, 0, res);
return res.toString();
}
//生成以node为根节点,深度为depth的描述二叉树的字符串
private void generateBSTString(Node node, int depth, StringBuilder res) {
if (node == null) {
res.append(generateDepthString(depth) + "null\n");
return;
}
res.append(generateDepthString(depth) + node.e + "\n");
generateBSTString(node.left, depth + 1, res);
generateBSTString(node.right, depth + 1, res);
}
private String generateDepthString(int depth) {
StringBuilder res = new StringBuilder();
for (int i = 0; i < depth; i++) {
res.append("--");
}
return res.toString();
}
}
学习时间:
08:30-10:30 11:30-12:30 15:00-16:00
学习产出:
对于SSM框架的环境准备进行了系统的学习,同时学会了Spring与Mybatis的整合,对于以后基于SSM框架的开发有了一定的经验。
对于二分搜索树删除最大值和最小值进行了代码的实现,对于明天学习在二分搜索树中删除任意一个元素打下了基础。
本博客详细介绍了SSM框架环境的准备及Spring与Mybatis的整合,同时深入学习了二分搜索树的删除操作。通过实践,提高了在SSM框架下进行开发的能力,并为后续学习在二分搜索树中删除任意元素奠定了基础。
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