java-jdbc-mysql：实现数据库表的增删改查

以数据库test下数据表student（sno，sname，ssex，sage，sdept）为例：

student表中的已有的所有记录：

Java代码对表test.student的操作：

创建student类，包含String sno，String sname，String ssex，int sage，String sdept：

package jdbcTest;

public class Student {
    private String sno,sname,ssex,sdept;  //学号，姓名，性别，部门
    private int sage;  //年龄
    
    public Student(){}
    
    public Student(String sno,String sname,String sex,String dept,int age){
        this.sno = sno;
        this.sname = sname;
        this.ssex = sex;
        this.sdept=dept;
        this.sage = age;
    }
    
    public void setSno(String sno){
        this.sno = sno;
    }
    
    public String getSno(){
        return this.sno;
    }
    
    public void setSname(String sname){
        this.sname = sname;
    }
    
    public String getSname(){
        return this.sname;
    }
    
    public void setSsex(String sex){
        this.ssex = sex;
    }
    
    public String getSsex(){
        return this.ssex;
    }
    
    public void setSdept(String dept){
        this.sdept = dept;
    }
    
    public String getSdept(){
        return this.sdept;
    }
    
    public void setSage(int age){
        this.sage = age;
    }
    
    public int getSage(){
        return this.sage;
    }
    
    public String toString(){
        return this.sno+" "+this.sname+" "+this.ssex+" "+this.sage+" "+this.sdept;
    }
}

创建StudentDA类，用于数据库连接、操作数据库：

package jdbcTest;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class StudentDA {
    String driverName = "com.mysql.jdbc.Driver"; // 加载JDBC驱动
    String dbURL = "jdbc:mysql://localhost:3306/test"; // 连接服务器和数据库sample
    String userName = "test"; // 数据库用户名
    String userPwd = "test"; // 数据库密码
    static Connection dbConn = null;  //连接信息
    Statement statement;   //sql语句
    PreparedStatement pstatement;
    ResultSet rs;      //结果集
    
    //数据库连接
    public Connection dBConnection(){
        try {
            Class.forName(driverName);
            dbConn = DriverManager.getConnection(dbURL, userName, userPwd);
            System.out.println("Connection Succeed!");             
        } catch (Exception e) {
            System.out.println("Connection failed!");
            e.printStackTrace();
        }
        return dbConn;
    }
    
    //查询记录,将查询结果放在list中
    public List<Student> selectAllStudent(){
        List<Student> studentList = new ArrayList<Student>(); //存放查询结果
        String sql = "select * from student"; 
        
        try{
            statement = dbConn.createStatement();
            rs = statement.executeQuery(sql);  //执行sql语句并返回结果集
            while (rs.next()) {
                Student student = new Student();
                student.setSno(rs.getString("sno"));
                student.setSname(rs.getString("sname"));
                student.setSsex(rs.getString("ssex"));
                student.setSdept(rs.getString("sdept"));
                student.setSage(rs.getInt("sage"));
                studentList.add(student);  //将查询出的student信息放入studentList链表中
            }  
        }catch(Exception e){
            e.printStackTrace();
        }
/*        finally{
            try {
                statement.close();
                dbConn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }*/
        return studentList;        
    }
    
    //插入一个学生记录,如果插入成功，返回true
    public boolean insertStudent(Student stu){
        int i = 0; 
        String sqlInset = "insert into test.student(sno,sname,ssex,sage,sdept)" +
    " values(?, ?, ?, ?,?)";   //插入语句
         
         try {
            pstatement = dbConn.prepareStatement(sqlInset);
            pstatement.setString(1, stu.getSno()); //设置SQL语句第一个“？”的值
            pstatement.setString(2,stu.getSname());
            pstatement.setString(3,stu.getSsex());
            pstatement.setInt(4, stu.getSage());
            pstatement.setString(5,stu.getSdept());
            i = pstatement.executeUpdate();  //执行插入数据操作，返回影响的行数
            if(i == 1){       //如果插入数据成功，则影响的行数为1
                return true;
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return false;
    }
    
    //根据sno删除记录
    public boolean deleteStudent(String sno){
        int i = 0; 
        String sqlDelete = "delete from test.student where sno = " + sno; 
        
        try {
            pstatement = dbConn.prepareStatement(sqlDelete);
            i = pstatement.executeUpdate();  //执行删除数据操作，返回影响的行数
            if(i == 1){       //如果删除数据成功，则影响的行数为1
                return true;
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return false;
    }
    
    //删除所有的记录
    public void deleteAll(){
        String sqlDeleteAll = "delete from student";
        try {
            pstatement = dbConn.prepareStatement(sqlDeleteAll);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    //根据学号sno，更新学生年龄sage
    public boolean updateStudent(String sno,int age){
        int i =0;
        String sqlUpdate = "update test.student set sage=? where sno=?";
        try {
            pstatement = dbConn.prepareStatement(sqlUpdate);
            pstatement.setInt(1,age); //设置SQL语句第一个"?"的参数值
            pstatement.setString(2, sno); 
            i = pstatement.executeUpdate(); //执行修改操作，返回影响的行数
            if(i == 1){          //修改成功返回true
                return true;
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }    
        return false;        
    }

    //测试增删改查
    public static void main(String args[]){
        StudentDA stuDA = new StudentDA();
        dbConn = stuDA.dBConnection(); 
        //测试查询
        System.out.println("测试----查询所有记录 ");
        List<Student> stuList = stuDA.selectAllStudent();
        for(Student stu:stuList){
            System.out.println(stu.toString());
        }

/*        //测试插入
        System.out.println("测试----插入一条记录 ");
        Student stu = new Student("200215334","test2","男","CS",25);
        if(stuDA.insertStudent(stu)){
            System.out.println("插入成功");
        }else{
            System.out.println("插入失败");
        }
        
        //测试根据sno删除记录
        if(stuDA.deleteStudent("200215334")){
            System.out.println("删除成功");
        }else{
            System.out.println("删除失败");
        }
        
        //测试更新
        if(stuDA.updateStudent("200215333", 33)){
            System.out.println("更新成功");
        }else{
            System.out.println("更新失败");
        }*/
    }
}