在java中对数据库进行增删改查

1.java连接MySql数据库

代码区域：

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package com.oracle.jdbc.demo1;   import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException;   public class JDBCDemo {           //四个属性（四个常量的字符串）     /*     jdbcName     url     user     password     */     private static final String jdbcName="com.mysql.jdbc.Driver";     private static final String url="jdbc:mysql://127.0.0.1:3306/emp_dept";     private static final String user="root";     private static final String password="123456";     /*      * 一个类（DriverManeger）四个接口（Connection、）      * */     public static void main(String[] args) {         // TODO Auto-generated method stub         Connection conn=null;         try {             Class.forName(jdbcName);             conn=DriverManager.getConnection(url, user, password);             //获得conn就表示获取了数据库的连接             System.out.println("连接数据库成功");         } catch (Exception e) {             e.printStackTrace();         } finally {             try {                 conn.close();             } catch (SQLException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }         }     }   }

　　

2.在java中向数据库添加数据

第一种方法：添加数据

 

代码区域：

 

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package com.oracle.jdbc.demo2;   import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException;   public class JDBCAdd {     private static final String jdbcName="com.mysql.jdbc.Driver";     private static final String url="jdbc:mysql://127.0.0.1:3306/emp_dept";     private static final String user="root";     private static final String password="123456";     /*      * 一个类（DriverManeger）四个接口（Connection、PreparedStatement、）      * */     public static void main(String[] args) {         // TODO Auto-generated method stub         Connection conn=null;         try {             Class.forName(jdbcName);             conn=DriverManager.getConnection(url, user, password);             //增加数据的操作             String name="田雨";             String sex="女";             String sql="insert into person values(null,'"+name+"','"+sex+"')";             PreparedStatement pst=conn.prepareStatement(sql); //准备执行sql语句             int i=pst.executeUpdate(); //返回成功插入数据的行数                           System.out.println("成功添加了"+i+"条记录");                       } catch (Exception e) {             e.printStackTrace();         } finally {             try {                 conn.close();             } catch (SQLException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }         }     } }

　　

第二中方法：添加数据

代码区域：

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package com.oracle.jdbc.demo2;   import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException;   public class JDBCAdd2 {           private static final String jdbcName="com.mysql.jdbc.Driver";     private static final String url="jdbc:mysql://127.0.0.1:3306/emp_dept";     private static final String user="root";     private static final String password="123456";     /*      * 一个类（DriverManeger）四个接口（Connection、PreparedStatement、）      * */     public static void main(String[] args) {         // TODO Auto-generated method stub         Connection conn=null;         try {             Class.forName(jdbcName);             conn=DriverManager.getConnection(url, user, password);             //增加数据的操作             String name="田雨2";             String sex="女";             String sql="insert into person values(null,?,?)";             PreparedStatement pst=conn.prepareStatement(sql); //准备执行sql语句             pst.setString(1, name); //填充第1个问好             pst.setString(2, sex); //填充第2个问好             int i=pst.executeUpdate(); //返回成功插入数据的行数                           System.out.println("成功添加了"+i+"条记录");                       } catch (Exception e) {             e.printStackTrace();         } finally {             try {                 conn.close();             } catch (SQLException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }         }     }   }

　　

3.在java中修改数据库的内容

 

代码区域：

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package com.oracle.jdbc.demo3;   import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException;   public class JDBCModify {       private static final String jdbcName="com.mysql.jdbc.Driver";     private static final String url="jdbc:mysql://127.0.0.1:3306/emp_dept";     private static final String user="root";     private static final String password="123456";     /*      * 一个类（DriverManeger）四个接口（Connection、PreparedStatement、）      * */     public static void main(String[] args) {         // TODO Auto-generated method stub         Connection conn=null;         try {             Class.forName(jdbcName);             conn=DriverManager.getConnection(url, user, password);             //修改数据的操作             int id=2;             String name="王希宝";             String sex="男";             String sql="update person set name=?,sex=? where id=?";             PreparedStatement pst=conn.prepareStatement(sql); //准备执行sql语句             pst.setString(1, name); //填充第1个问好             pst.setString(2, sex); //填充第2个问好             pst.setInt(3, id);             int i=pst.executeUpdate(); //返回成功修改数据的行数                    System.out.println("成功修改了"+i+"条记录");                    } catch (Exception e) {             e.printStackTrace();         } finally {             try {                 conn.close();             } catch (SQLException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }         }     } }

　　

4.在java中删除数据库的内容

代码区域： 

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package com.oracle.jdbc.demo4;   import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException;   public class JDBCDel {           private static final String jdbcName="com.mysql.jdbc.Driver";     private static final String url="jdbc:mysql://127.0.0.1:3306/emp_dept";     private static final String user="root";     private static final String password="123456";     /*      * 一个类（DriverManeger）四个接口（Connection、PreparedStatement、）      * */     public static void main(String[] args) {         // TODO Auto-generated method stub         Connection conn=null;         try {             Class.forName(jdbcName);             conn=DriverManager.getConnection(url, user, password);             //删除数据的操作             int id=2;               String sql="delete from person where id=?";             PreparedStatement pst=conn.prepareStatement(sql); //准备执行sql语句             pst.setInt(1, id);             int i=pst.executeUpdate(); //返回成功删除数据的行数                           System.out.println("成功删除了"+i+"条记录");                       } catch (Exception e) {             e.printStackTrace();         } finally {             try {                 conn.close();             } catch (SQLException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }         }     }   }

　　

5.在java中查看数据库的内容

 代码区域：

 

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package com.oracle.jdbc.demo5;   import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException;   public class JDBCFindAll {           private static final String jdbcName="com.mysql.jdbc.Driver";     private static final String url="jdbc:mysql://127.0.0.1:3306/emp_dept";     private static final String user="root";     private static final String password="123456";     /*      * 一个类（DriverManeger）四个接口（Connection、PreparedStatement、ResultSet、）      * */     public static void main(String[] args) {         // TODO Auto-generated method stub         Connection conn=null;         try {             Class.forName(jdbcName);             conn=DriverManager.getConnection(url, user, password);             //查询数据的操作             String sql="select id,name,sex from person";             PreparedStatement pst=conn.prepareStatement(sql); //准备执行sql语句             ResultSet rs=pst.executeQuery();             while(rs.next()){                 int id=rs.getInt("id");                 String name=rs.getString("name");                 String sex=rs.getString("sex");                 System.out.println(id+" "+name+" "+sex);             }                       } catch (Exception e) {             e.printStackTrace();         } finally {             try {                 conn.close();             } catch (SQLException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }         }     }   }