JDBC的详细实现
首先是Idea和mysql的安装
具体参考下面一篇博客:
Idea mysql安装
下面是数据库中的表:
1. 加载JDBC驱动管理器(将与mysql连接的相应jar包导入Idea中):
jar包去mysql官网下载添加链接描述
点击DOWNLOADS->COMMUNITY-MYSQLConnectors->Connector/J;
(下载到一个没有中文的路径)
右键点击工程->new->directory->名字为lib->将jar包复制粘贴到lib文件下;
这样就加载好了JDBC驱动器
2. 连接数据库及释放:
Connection connection=null;//声明
PreparedStatement statement=null;
ResultSet resultSet=null;
try {
Class.forName("com.mysql.jdbc.Driver");
//创建连接
connection=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/jdbc?useSSL=true&"+"characterEncoding=utf-8&user=root&password=root");
System.out.println("创建成功");
}catch (Exception e) {
e.printStackTrace();
}
...
//释放连接
finally {//关闭资源
if(resultSet!=null){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(statement!=null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(connection!=null){//为空的话会报错
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
3. 查询操作:
String sql="select * from user";
//跳到statement对象
statement=connection.prepareStatement(sql);
//执行sql得到结果类
resultSet=statement.executeQuery();
//关闭处理结果类
while (resultSet.next()){
System.out.println(resultSet.getInt(1));
System.out.println(resultSet.getString(2));
System.out.println(resultSet.getInt(3));
System.out.println(resultSet.getString(4));
System.out.println(resultSet.getString(5));
}
4. 增添操作
String sql="insert into user( name ,age, sex,salary) value(?,?,?,?)";
//得到statement对象
statement=connection.prepareStatement(sql);
statement.setString(1,"大眼");
statement.setInt(2,27);
statement.setString(3,"女");
statement.setString(4,"3000");
statement.executeUpdate();
System.out.println("插入成功!");
5. 修改操作:
String sql="update user set name='剑魔', age=32 ,sex='男' ,salary=6000 where id=1";
statement=connection.prepareStatement(sql);
statement.executeUpdate();
System.out.println("修改成功");
6.删除操作:
String sql="delete from user where id=4";
statement=connection.prepareStatement(sql);
statement.executeUpdate();
System.out.println("删除成功");
7. user类:
package com.jdbc.model;
//实体类 去创造用户实体
//[封装]:类封装 getter/setter访问器 属性 构造方法 tostring()
//继承 接口 抽象
public class user {
private String username;
private int age;
private String sex;
private String salary;
//getter和setter 使用快捷键
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getSalary() {
return salary;
}
public void setSalary(String salary) {
this.salary = salary;
}
public user() {
}
@Override
public String toString() {
return "user{" +
"username='" + username + '\'' +
", age=" + age +
", sex='" + sex + '\'' +
", salary='" + salary + '\'' +
'}';
}
}