package cn.com.JDBC;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

public class CRUD {

public static void main(String[] args) throws SQLException {

// TODO Auto-generated method stub

//create();

//update();

delete();

read();

}

static void delete() throws SQLException

{

Connection conn=null;

Statement st=null;

ResultSet resultset=null;

try {

//2.建立连接

conn=JdbcUtils.getConnection();

//单例设计模式

conn=JdbcUtilsSingle.getInstance().getConnection();

//3.创建语句

st=conn.createStatement();

//4.执行语句

String sql="delete from user where id>5";

int i=st.executeUpdate(sql);

System.out.println("i="+i);

} finally

{

JdbcUtils.free(resultset, st, conn);

}

}

static void update() throws SQLException

{

Connection conn=null;

Statement st=null;

ResultSet resultset=null;

try {

//2.建立连接

conn=JdbcUtils.getConnection();

//单例设计模式

conn=JdbcUtilsSingle.getInstance().getConnection();

//3.创建语句

st=conn.createStatement();

//4.执行语句

String sql="update user set money=money+20";

int i=st.executeUpdate(sql);

System.out.println("i="+i);

} finally

{

JdbcUtils.free(resultset, st, conn);

}

}

static void create() throws SQLException

{

Connection conn=null;

Statement st=null;

ResultSet resultset=null;

try {

//2.建立连接

conn=JdbcUtils.getConnection();

//单例设计模式

conn=JdbcUtilsSingle.getInstance().getConnection();

//3.创建语句

st=conn.createStatement();

//4.执行语句

String sql="insert into user(name,birthday,money) values('wy','2011-09-23','2894656')";

int i=st.executeUpdate(sql);

System.out.println("i="+i);

} finally

{

JdbcUtils.free(resultset, st, conn);

}

}

static void read() throws SQLException

{

Connection conn=null;

Statement st=null;

ResultSet resultset=null;

try {

//2.建立连接

conn=JdbcUtils.getConnection();

//单例设计模式

conn=JdbcUtilsSingle.getInstance().getConnection();

//3.创建语句

st=conn.createStatement();

//4.执行语句

resultset=st.executeQuery("select id,name,birthday,money from user");

//5.处理结果

while(resultset.next())

{

System.out.println(resultset.getObject("id"));

System.out.println(resultset.getObject("name"));

System.out.println(resultset.getObject("birthday"));

System.out.println(resultset.getObject("money"));

}

} finally

{

JdbcUtils.free(resultset, st, conn);

}

}

}

package cn.com.JDBC;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

public class JdbcUtils 

{

private static String url="jdbc:mysql://localhost:3306/jdbc";

private static String user="root";

private static String password="123";

private JdbcUtils()

{

}

static

{

try

{

Class.forName("com.mysql.jdbc.Driver");

}

catch(ClassNotFoundException e)

{

throw new ExceptionInInitializerError(e);

}

}

public static Connection getConnection() throws SQLException

{

return DriverManager.getConnection(url, user, password);

}

public static void free(ResultSet resultset,Statement st,Connection conn)

{

//6.释放资源

try{

if(resultset!=null)

resultset.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

finally

{

try

{

if(st!=null)

st.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

finally

{

if(conn!=null)

try {

conn.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

}

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