myeclipse连接mysql数据库以及对数据库的增删改查

1、下载mysql的jdbc驱动包，将驱动包放入新建的文件夹中（点击下载）



2、任意建一个test数据表



3、新建一个file文件后缀为.properties并添加相对应的数据



4、工具类DBConnectionUtil .java

package com.ljr.util;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

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.Properties;

public class DBConnectionUtil {

private static String jdbcDriver="";

private static String jdbcURL="";

private static String jdbcUser="";

private static String jdbcPassword="";

static{

InputStream is=DBConnectionUtil.class.getClassLoader().getResourceAsStream("JDBC.properties");

Properties p=new Properties();

try {

p.load(is);

jdbcDriver=p.getProperty("jdbcDriver");

jdbcURL=p.getProperty("jdbcURL");

jdbcUser=p.getProperty("jdbcUser");

jdbcPassword=p.getProperty("jdbcPassword");

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public static Connection getConnection(){

Connection conn=null;

try {

Class.forName(jdbcDriver);

try {

conn=DriverManager.getConnection(jdbcURL,jdbcUser,jdbcPassword);

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return conn;

}

public static void closeAll(Statement st,Connection conn){

if(st !=null){

try {

st.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();
}

finally{

if(conn !=null){

try {

conn.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

}

public static void closeAll2(PreparedStatement st,Connection conn,ResultSet rs){

if(rs!=null){

try {

rs.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(st !=null){

try {

st.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

finally{

if(conn !=null){

try {

conn.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

}

}

5、实体类User.java

package com.ljr.po;

public class User {

private int userId;

public int getUserId() {

return userId;

}

public void setUserId(int userId) {

this.userId = userId;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public int getSex() {

return sex;

}

public void setSex(int sex) {

this.sex = sex;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

public int getFlag() {

return flag;

}

public void setFlag(int flag) {

this.flag = flag;

}

private String username;

private int sex;

private String password;

private int flag;

}

6、UserDao.java

package com.ljr.dao;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import com.ljr.po.User;

import com.ljr.util.DBConnectionUtil;

public class UserDao {

public UserDao(){

}

public boolean saveUser(User user){

boolean flag=false;

Connection conn=null;

PreparedStatement st=null;

try {

conn=DBConnectionUtil.getConnection();

String sql="insert into user(username,password) values(?,?)";

st =conn.prepareStatement(sql);

st.setString(1,user.getUsername());

st.setString(2,user.getPassword());

int rows=st.executeUpdate();

if(rows>0){

flag=true;

System.out.println(sql);

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

System.out.println(".......");

DBConnectionUtil.closeAll(st, conn);

System.out.println("aaaaaaa");

}

return flag;

}

public boolean deleteUderByUserId(int userId){

boolean flag=false;

Connection conn=null;

PreparedStatement st=null;

try {

conn=DBConnectionUtil.getConnection();

String sql="delete from user where userId=?";

st=conn.prepareStatement(sql);

st.setInt(1, userId);

int rows=st.executeUpdate();

if(rows>0){

flag=true;

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

DBConnectionUtil.closeAll(st, conn);

}

return flag;

}

public boolean updateUserByMap(Map<String, Object> map){

boolean flag=false;

Connection conn=null;

PreparedStatement st=null;

try {

conn=DBConnectionUtil.getConnection();

String sql="update user set username=? where userId=?";

st=conn.prepareStatement(sql);

st.setString(1, (String)map.get("username"));

st.setString(2, (String)map.get("userId"));

int rows=st.executeUpdate();

if(rows>0){

flag=true;

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

DBConnectionUtil.closeAll(st, conn);

}

return flag;

}

public User getUserByUserId(int userId){

User user=null;

Connection conn=null;

PreparedStatement pr=null;

ResultSet rs=null;

String sql="select * from user where userId=?";

try {

conn=DBConnectionUtil.getConnection();

pr=conn.prepareStatement(sql);

pr.setInt(1, userId);

rs=pr.executeQuery();

if(rs.next()){

user=new User();

user.setUserId(rs.getInt("userId"));

user.setUsername(rs.getString("username"));

user.setFlag(rs.getInt("flag"));

user.setPassword(rs.getString("password"));

user.setSex(rs.getInt("sex"));

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

DBConnectionUtil.closeAll2(pr,conn, rs);

}

return null;

}

public List<User> getAllUserList(){

List<User> userlist=new ArrayList<User>();

Connection conn=null;

PreparedStatement pr=null;

ResultSet rs=null;

String sql="select * from user";

try {

conn=DBConnectionUtil.getConnection();

pr=conn.prepareStatement(sql);

rs=pr.executeQuery();

while(rs.next()){

User user=new User();

user.setUserId(rs.getInt("userId"));

user.setUsername(rs.getString("username"));

user.setFlag(rs.getInt("flag"));

user.setPassword(rs.getString("password"));

user.setSex(rs.getInt("sex"));

userlist.add(user);

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally{

DBConnectionUtil.closeAll2(pr,conn, rs);

}

return null;

}

}

7、测试类UserDaotest .java

package com.ljr.test;

import java.util.HashMap;

import java.util.Map;

import org.junit.Test;

import com.ljr.dao.UserDao;

import com.ljr.po.User;

public class UserDaotest {
UserDao userdao=new UserDao();

@Test

public void testSaveUser() throws Exception{
String username="哈哈mmm";
String password="11111";
User user=new User();
user.setUsername(username);
user.setPassword(password);
System.out.println(userdao.saveUser(user));

}

@Test

public void testSaveUser2() throws Exception{
String username="呜呜呜";
String password="11111";
User user=new User();
user.setUsername(username);
user.setPassword(password);
System.out.println(userdao.saveUser(user));

}

@Test

public void deleteUderByUserId() throws Exception{
System.out.println(userdao.deleteUderByUserId(4));

}

@Test

public void deleteUderByUserId2() throws Exception{
System.out.println(userdao.deleteUderByUserId(4));

}

@Test

public void updateUserByMap() throws Exception{
Map<String, Object> map=new HashMap<String, Object>();
map.put("username", "去去去");

    map.put("userId", "6");

    System.out.println(userdao.updateUserByMap(map));

}

@Test

public void updateUserByMap2() throws Exception{
Map<String, Object> map=new HashMap<String, Object>();
map.put("username", "去去去");

    map.put("userId", "6");

    System.out.println(userdao.updateUserByMap(map));

}

@Test

public void getUserByUserId() throws Exception{
UserDao userdao=new UserDao();
User user=userdao.getUserByUserId(10);
System.out.println(user.getUsername()+user.getUsername()+user.getFlag()+user.getPassword()+user.getSex());

}

}