开始准备工作，需要先把jdbc包引入。如下图。
有了上面划红线的那个包之后，下面是实现增删改查的全部代码，有注释。
差点忘了，还需要准备好数据库表，如下图，一个库：test，一个表user，三个字段，name、age、sex
package test;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
public class TestJdbc {
private static Connection getConn(){//链接数据库
Connection conn = null;
String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";
String username = "root";
String password = "root";
try {
Class.forName(driver); //classLoader,加载对应驱动
conn = (Connection) DriverManager.getConnection(url, username, password);
} catch (Exception e) {
//可以什么都不写
throw new RuntimeException(e);
}
return conn;
}
private static int insert(String name , String age, String sex){//新增数据
int a = 0;
Connection conn = getConn();
String sql = "insert into user (name, age , sex) value (?, ?, ?)";
PreparedStatement pstmt;
try{
pstmt = (PreparedStatement) conn.prepareStatement(sql);
pstmt.setString(1, name);
pstmt.setString(2, age);
pstmt.setString(3, sex);
a = pstmt.executeUpdate();
System.out.println("新增数量: " + a);
pstmt.close();
conn.close();
}catch(Exception e){
//可以什么都不写
}
return a;
}
private static int update(String age, String name) {//更新数据
Connection conn = getConn();
int i = 0;
String sql = "update user set age= ? where name= ? ";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement) conn.prepareStatement(sql);
pstmt.setString(1, age);
pstmt.setString(2, name);
i = pstmt.executeUpdate();
System.out.println("更新数据量: " + i);
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
return i;
}
private static Integer getAll() {//查询数据
Connection conn = getConn();
String sql = "select * from user";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement)conn.prepareStatement(sql);
ResultSet rs = pstmt.executeQuery();
int col = rs.getMetaData().getColumnCount();
System.out.println("===========================================");
while (rs.next()) {
for (int i = 1; i <= col; i++) {
System.out.print(rs.getString(i) + "\t");
if ((i == 2) && (rs.getString(i).length() < 8)) {
System.out.print("\t");
}
}
System.out.println("");
}
System.out.println("=========================================");
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
private static int delete(String name) {//删除数据
Connection conn = getConn();
int i = 0;
String sql = "delete from user where name= ? ";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement) conn.prepareStatement(sql);
pstmt.setString(1, name);
i = pstmt.executeUpdate();
System.out.println("删除数量: " + i);
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
return i;
}
public static void main(String[] args){
insert("万磁王", "1500", "白袍巫师");
getAll();
update("800", "万磁王");
getAll();
delete("万磁王");
getAll();
}
}
运行之后输出结果：
新增数量: 1 =========================================== tom 88 man 孙悟空 99999 齐天大圣 万磁王 1500 白袍巫师 ========================================= 更新数据量: 1 =========================================== tom 88 man 孙悟空 99999 齐天大圣 万磁王 800 白袍巫师 ========================================= 删除数量: 1 =========================================== tom 88 man 孙悟空 99999 齐天大圣 =========================================
初学的小朋友们有看不明白的地方就在下面留言吧