JDBC配置connector的jar包
1.项目下新建lib文件夹
2.将mysql-connector-java-版本号.jar复制到lib目录下
3.右键项目名,选择Properties选项
4.点击Add JARS...,选中刚复制的jar包后,点击Apply=》OK
连接数据库
连接的过程
1)加载驱动
2)创建连接对象
3)创建执行对象
4)执行sql语句
5)处理返回结果
6)关闭访问资源
public class JdbcDemo01{
public static final String URL = "jdbc:mysql://localhost:3306/situ001?serverTimezone=UTC&useSSL=false";//&useSSL=false可不加,serverTimezone=UTC表示时区
public static final String USER = "root";
public static final String PASS = "123456";
static Connection conn = null;
static PrepareStatement ps = null;
static ResultSet rs = null;
//建立数据库连接
public static void init(){
try{
//加载驱动
Class.forName("com.mysql.cj.jdbc.Driver");
//建立连接
conn = DriverManager.getConnection(URL,USER,PASS);
System.out.println("建立连接成功");
}catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
//查询
public static void query(String sql){
init();
try{
ps = conn.prepareStatement(sql);
rs = ps.excuteQuery(sql);
while(rs.next()){
System.out.println(rs.getInt("id")+","+rs.getString("s_name"));
}
}catch (SQLException e) {
e.printStackTrace();
}finally{
close();
}
}
//修改表(增删改)
public static void excute(String sql){
init();
try{
ps = conn.prepareStatement(sql);
int rows = ps.excuteUpdate(sql);
if(rows == 0) System.out.println("没有改变表中的记录");
System.out.println("修改成功");
}catch (SQLException e) {
e.printStackTrace();
}finally{
close();
}
//添加一条数据同时返回其主键
public static Integer addReturnPK(String sql){
init();
try{
ps = conn.prepareStatement(sql,ps.RETURN_GENERATED_KEYS);
int rows = ps.excuteUpdate();
if(rows == 0) return null;
Result rs2 = ps.getGeneratedKeys();
Integer id = null;
while(rs2.next()){
id = rs2.getInt(1);
}
return id;
}catch (SQLException e) {
e.printStackTrace();
return null;
}finally{
close();
}
}
//关闭连接
public static void close(){
try {
if(rs != null) rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
if(ps != null) ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
if(conn != null) conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void main(String[] args){
//测试查询方法
String sql = "select*from student";
}
}
查询 和 增删改方法的优化(输入参数)
public static void excute(String sql, String name, Integer age){
init();
try {
ps = conn.prepareStatement(sql);
ps.setString(1, name);
ps.setInt(2, age);
int rows = ps.executeUpdate();
if (rows >0) {
System.out.println("执行成功");
}else{
System.out.println("没有影响记录");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("执行失败");
}finally {
close();
}
}
public static void query(String sql, Integer id,String name){
init();
try {
ps = conn.prepareStatement(sql);
ps.setInt(1, id);
ps.setString(2, name);
rs = ps.executeQuery();
while(rs.next()){
System.out.println(rs.getInt("id")+","+rs.getString("s_name"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
close();
}
}
标签:ps,JDBC,Java,String,public,static,sql,catch,主键
From: https://www.cnblogs.com/xiaoto9426/p/16848022.html