JDBC 增加，选择，修改，删除操作示例

//静态模式

package cn.eboy.jdbc;

import java.sql.*;

public final class JdbcUtils {
    private static String url = "jdbc:mysql://127.0.0.1:3306/ssh?useUnicode=true&characterEncoding=GBK";
    private static String user = "root";
    private static String password = "123456";
    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 rs, Statement st, Connection conn){
        try{
            if (rs != null){
                rs.close();    
            }
        }catch (SQLException e){
                e.printStackTrace();
        }finally{
            try{
                if (st != null){
                    st.close();    
                }
            }catch (SQLException e){
                e.printStackTrace();
            }finally{
                if (conn != null){
                    try{
                        conn.close();
                    }catch (SQLException e){
                        e.printStackTrace();
                    }    
                }
            }
        }
    }    
}

 

//JDBC 查询，增加，修改，删除

package cn.eboy.jdbc;

import cn.eboy.jdbc.JdbcUtils;

public class CRUD {

    public static void main(String[] args) {
        try {
            insert();
            select();
            update();
            delete();
        } catch (Exception e) {            
            e.printStackTrace();
        }
    }
    
    static void select() throws Exception {
        java.sql.Connection conn = null;
        java.sql.Statement st = null;
        java.sql.ResultSet rs = null;        
        String sql = "select id, username, password from user";
        try {            
            //2.建立连接，可选指定编码及字符集
            conn = JdbcUtils.getConnection();            
            //3.创建语句
            st = conn.createStatement();
            //4.执行语句
            rs = st.executeQuery(sql);
            //5.处理结果
            while (rs.next()){
                System.out.println(rs.getString("id") + "\t" + 
                                   rs.getObject("username") + "\t" + 
                                   rs.getObject("password"));
            }
        } finally {
            JdbcUtils.free(rs, st, conn);            
        }
    }
    
    static void insert() throws Exception {
        java.sql.Connection conn = null;
        java.sql.Statement st = null;
        java.sql.ResultSet rs = null;        
        String sql = "insert into user(username, password)values('eboy', 'dxawihty')";
        try {            
            //2.建立连接，可选指定编码及字符集
            conn = JdbcUtils.getConnection();            
            //3.创建语句
            st = conn.createStatement();
            //4.执行语句
            int i = st.executeUpdate(sql);
            //5.处理结果        
            System.out.println("Result: " + i);
        } finally {
            JdbcUtils.free(rs, st, conn);            
        }
    }
    
    static void update() throws Exception {
        java.sql.Connection conn = null;
        java.sql.Statement st = null;
        java.sql.ResultSet rs = null;        
        String sql = "update user set password='gxy850318' where username = 'eboy'";
        try {            
            //2.建立连接，可选指定编码及字符集
            conn = JdbcUtils.getConnection();            
            //3.创建语句
            st = conn.createStatement();
            //4.执行语句
            int i = st.executeUpdate(sql);
            //5.处理结果        
            System.out.println("Result: " + i);
        } finally {
            JdbcUtils.free(rs, st, conn);            
        }
    }
    
    static void delete() throws Exception {
        java.sql.Connection conn = null;
        java.sql.Statement st = null;
        java.sql.ResultSet rs = null;        
        String sql = "delete from user";
        try {            
            //2.建立连接，可选指定编码及字符集
            conn = JdbcUtils.getConnection();            
            //3.创建语句
            st = conn.createStatement();
            //4.执行语句
            int i = st.executeUpdate(sql);
            //5.处理结果        
            System.out.println("Result: " + i);
        } finally {
            JdbcUtils.free(rs, st, conn);            
        }
    }
}