jdbc里一个最靠谱的连接demo

最靠谱的jdbc连接例子

包括增删改,查一条数据,查所有数据。

Bean.java

public class Bean {
private String id;
private String number;
private String name;
private String score;

public String getNumber() {
return number;
}

public void setNumber(String number) {
this.number = number;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

 

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getScore() {
return score;
}

public void setScore(String score) {
this.score = score;
}

@Override
public String toString() {
return "Bean [id=" + id + ", number=" + number + ", name=" + name
+ ", score=" + score + "]";
}

}

JdbcUtils.java

import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.ResultSet;
import com.mysql.jdbc.Statement;

public class JdbcUtils {

private static String url="jdbc:mysql://127.0.0.1:3306/data1702?characterEncoding=UTF-8";
private static String user="root";
private static String password="123456";
//加载驱动(只加载一次)
static{
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//获得连接(静态方法独立于对象)
public static Connection getConnect() throws SQLException{
java.sql.Connection c =DriverManager.getConnection(url,user,password);
return (Connection) c;
}
//释放连接
public static void release(Statement stmt,Connection conn){
try {
stmt.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void release(ResultSet rs,PreparedStatement pstmt,Connection conn){
try {
rs.close();
pstmt.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

BeanDao.java

import java.sql.*;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.mysql.jdbc.*;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;

public class BeanDao {
// 增加一个学生
public boolean insert(String id, String number, String name, String score)
throws SQLException {
Bean b = new Bean();
int flag = 0;
Connection con = JdbcUtils.getConnect();
String sql = "insert into user (id,number,name,score) values (?, ?, ?, ?)";
PreparedStatement pstmt = con.prepareStatement(sql);
pstmt.setString(1, id);
pstmt.setString(2, number);
pstmt.setString(3, name);
pstmt.setString(4, score);
try {
flag = pstmt.executeUpdate();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JdbcUtils.release((Statement) pstmt, con);
}
if (flag != 0) {
return true;
} else
return false;

}
//删除一条记录
public boolean delete(String id) throws SQLException{
int flag = 0;
Bean b=new Bean();
Connection con = JdbcUtils.getConnect();
String sql="delete from user where id=?";
PreparedStatement pstmt=con.prepareStatement(sql);
pstmt.setString(1, id);
try {
flag=pstmt.executeUpdate();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JdbcUtils.release((Statement) pstmt, con);
}
if(flag!=0)
return true;
else
return false;

}
//修改分数
public boolean update(String id,String score) throws SQLException{
int flag = 0;
Bean b=new Bean();
Connection con = JdbcUtils.getConnect();
String sql="update user set score = ? where id = ?";
PreparedStatement pstmt=con.prepareStatement(sql);
pstmt.setString(1, score);
pstmt.setString(2, id);
try {
flag=pstmt.executeUpdate();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JdbcUtils.release((Statement) pstmt, con);
}
if(flag!=0)
return true;
else
return false;
}
//查看一条数据
public Bean select(String id) throws SQLException{
ResultSet rs=null;
Bean b=new Bean();
Connection con = JdbcUtils.getConnect();
String sql="select * from user where id = ?";
PreparedStatement pstmt=con.prepareStatement(sql);
pstmt.setString(1, id);
try {
rs=pstmt.executeQuery();
if(rs.next()){
b.setId(rs.getString("id"));
b.setNumber(rs.getString("number"));
b.setName(rs.getString("name"));
b.setScore(rs.getString("score"));
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JdbcUtils.release((com.mysql.jdbc.ResultSet) rs, pstmt, con);
}
return b;
}
public List<Bean> selectAll() throws SQLException{
ResultSet rs=null;
Bean b;
List<Bean> list = new ArrayList<Bean>();
Connection con = JdbcUtils.getConnect();
String sql="select * from user";
PreparedStatement pstmt=con.prepareStatement(sql);
try {
rs=pstmt.executeQuery();
while(rs.next()){
b=new Bean();
b.setId(rs.getString("id"));
b.setNumber(rs.getString("number"));
b.setName(rs.getString("name"));
b.setScore(rs.getString("score"));
list.add(b);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JdbcUtils.release((com.mysql.jdbc.ResultSet) rs, pstmt, con);
}
return list;
}

}

TestJDBC.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class TestJDBC {
public static void main(String[] args) throws SQLException {
Bean b=new Bean();
/*
测试插入
b.setId("101");
b.setNumber("1700130221");
b.setName("wangpeng");
b.setScore("100");
BeanDao bdao=new BeanDao();
boolean flag=bdao.insert(b.getId(),b.getNumber(),b.getName(),b.getScore());
System.out.println(flag);*/
/*
测试删除
b.setId("101");
BeanDao bdao=new BeanDao();
boolean flag=bdao.delete(b.getId());
System.out.println(flag);
*/

//测试修改分数
/*b.setId("100");
b.setScore("0");
BeanDao bdao=new BeanDao();
boolean flag=bdao.update(b.getId(), b.getScore());
System.out.println(flag);
*/

//查看数据库的一条数据
/*b.setId("100");
BeanDao bdao=new BeanDao();
b=bdao.select(b.getId());
System.out.println(b.getId()+" | "+b.getNumber()+" | "+b.getName()+" | "+b.getScore());*/

//查看数据库所有信息
/*BeanDao bdao=new BeanDao();
List<Bean> list=bdao.selectAll();
for(Bean x:list){
System.out.println(x);
}
*/

}
}