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使用PreparedStatement执行sql语句
存储过程：
CREATE TABLE users(
id INT PRIMARY KEY AUTO_INCREMENT,
NAME VARCHAR(20),
PASSWORD VARCHAR(20)
);
INSERT INTO users(NAME, PASSWORD) VALUES("木丁西", "1234");
INSERT INTO users(NAME, PASSWORD) VALUES("admin", "admin");
SELECT * FROM users WHERE NAME ='admin' AND PASSWORD='admin2' OR 1=1;
-- 创建带有输入参数的存储过程
DELIMITER $
CREATE PROCEDURE pro_findById(IN uid INT)
BEGIN
SELECT * FROM users WHERE id = uid;
END $
-- 创建带有输入输出参数的存储过程
DELIMITER $
CREATE PROCEDURE pro_getNameById(IN uid INT, OUT uname VARCHAR(20))
BEGIN
SELECT NAME INTO uname FROM users WHERE id = uid;
END $
CALL pro_getNameById(1, @NAME);
SELECT @NAME;
CREATE DATABASE infoSystem;
USE infoSystem;
CREATE TABLE contact(
id VARCHAR(32) PRIMARY KEY, -- 学号
NAME VARCHAR(20), -- 姓名
gender VARCHAR(2),
major VARCHAR(20), -- 专业班级
);
jdbc调用存储过程：
package com.cn.preparedStatement;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import org.junit.Test;
import com.cn.Util.JdbcUtil;
/**
* 使用PreparedStatement执行sql语句
* @author liuzhiyong
*
*/
public class Demo1 {
private Connection conn = null;
private PreparedStatement preStmt = null;
/**
* 使用PreparedStatement执行sql语句（增加）
*/
@Test
public void test1() {
try {
//1.获取连接
conn = JdbcUtil.getConnection();
//2.准备预编译的sql语句
String sql = "INSERT INTO employee(ename, gender, dept,email,phone) VALUES(?,?,?,?,?)";//?表示一个参数的占位符
//3.执行预编译sql语句（检查语法）
preStmt = conn.prepareStatement(sql);
/**
* 4.设置参数
* 参数1：参数位置 从1开始
* 参数2：参数值
*/
preStmt.setString(1, "李小乐");
preStmt.setString(2, "女");
preStmt.setString(3, "销售部");
preStmt.setString(4,
preStmt.setString(5, "18071897999");
//5.发送参数，执行sql
int count = preStmt.executeUpdate();
System.out.println(count);
} catch (Exception e) {
throw new RuntimeException(e);
}finally{
JdbcUtil.close(conn, preStmt);
}
}
/**
* 使用PreparedStatement执行sql语句（修改）
*/
@Test
public void test2() {
try {
//1.获取连接
conn = JdbcUtil.getConnection();
//2.准备预编译的sql语句
String sql = "UPDATE employee SET ename=? where eid = ?";//?表示一个参数的占位符
//3.执行预编译sql语句（检查语法）
preStmt = conn.prepareStatement(sql);
/**
* 4.设置参数
* 参数1：参数位置 从1开始
* 参数2：参数值
*/
preStmt.setString(1, "王宝强");
preStmt.setInt(2, 8);
//5.发送参数，执行sql
int count = preStmt.executeUpdate();
System.out.println(count);
} catch (Exception e) {
throw new RuntimeException(e);
}finally{
JdbcUtil.close(conn, preStmt);
}
}
/**
* 使用PreparedStatement执行sql语句（删除）
*/
@Test
public void test3() {
try {
//1.获取连接
conn = JdbcUtil.getConnection();
//2.准备预编译的sql语句
String sql = "delete from employee where eid = ?";//?表示一个参数的占位符
//3.执行预编译sql语句（检查语法）
preStmt = conn.prepareStatement(sql);
/**
* 4.设置参数
* 参数1：参数位置 从1开始
* 参数2：参数值
*/
preStmt.setInt(1, 8);
//5.发送参数，执行sql
int count = preStmt.executeUpdate();
System.out.println(count);
} catch (Exception e) {
throw new RuntimeException(e);
}finally{
JdbcUtil.close(conn, preStmt);
}
}
/**
* 使用PreparedStatement执行sql语句（查询）
*/
@Test
public void test4() {
ResultSet rs = null;
try {
//1.获取连接
conn = JdbcUtil.getConnection();
//2.准备预编译的sql语句
String sql = "select * from employee";
//3.执行预编译sql语句（检查语法）
preStmt = conn.prepareStatement(sql);
//4.无参数，则直接执行sql
rs = preStmt.executeQuery();
while(rs.next()){
System.out.println(rs.getInt(1) + "#" + rs.getString(2) + "#" + rs.getString(3) + "#" + rs.getString(4) + "#" + rs.getString(5) + "#" + rs.getString(6));
}
} catch (Exception e) {
throw new RuntimeException(e);
}finally{
JdbcUtil.close(conn, preStmt, rs);
}
}
}
————————————————
抽取jdbc获取Connection对象和关闭Connection对象和Statement对象的工具类
JdbcUtil.java
package com.cn.Util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
* jdbc的工具类
* @author liuzhiyong
*
*/
public class JdbcUtil {
private static String url = "jdbc:mysql://localhost:3306/mydb";
private static String user = "root";
private static String password = "root";
/**
* 静态代码块（只调用一次）
*/
static{
//注册驱动程序
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("驱动程序注册出错！");
}
}
/**
* 获取连接对象的方法
*/
public static Connection getConnection(){
try {
Connection conn = DriverManager.getConnection(url, user, password);
return conn;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
throw new RuntimeException(e);
}
}
/**
* 释放资源的方法
*/
public static void close(Connection conn, Statement stmt, ResultSet rs){
//关闭资源（顺序：后打开，先关闭）
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
System.out.println("ResultSet关闭失败！");
throw new RuntimeException(e);
}
}if(stmt != null){
try {
stmt.close();
} catch (SQLException e) {
System.out.println("Statement关闭失败！");
throw new RuntimeException(e);
}
}
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
System.out.println("Connection关闭失败！");
throw new RuntimeException(e);
}
}
}
public static void close(Connection conn, Statement stmt){
//关闭资源（顺序：后打开，先关闭）
if(stmt != null){
try {
stmt.close();
} catch (SQLException e) {
System.out.println("Statement关闭失败！");
throw new RuntimeException(e);
}
}
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
System.out.println("Connection关闭失败！");
throw new RuntimeException(e);
}
}
}
}
本文摘自 ：https://blog.51cto.com/u