按骨架创建项目
1. 选quick-start
2. 调整pom，添加依赖
3. 观察项目结构
一般过程
1. 创建pojo
2. 创建DBUtil
3. 创建测试
3.1 用main进行测试
3.2 用junit单元测试
连接数据库
1. 工具类封装
2. 工具类使用，完成CRUD操作
3. 通用DAO设计与实现
4. 专用DAO生成与实现
5. 测试DAO
具体文件参考
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.zfh</groupId>
<artifactId>maven-demo-quick-01</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>maven-demo-quick-01</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
</dependency>
</dependencies>
</project>
# 注意，这里，生成的是jar包
项目结构
具体java程序文档
User.java
package com.zfh.entity;
import java.util.Date;
import lombok.Data;
@Data
public class User {
private String id;
private String name;
private String gender;
private Date bir;
private Integer score;
}
DAO.java
package com.zfh;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.List;
import com.zfh.util.DBUtil;
public class DAO {
private DBUtil dbUtil = new DBUtil();
private Connection conn = dbUtil.getConn();
public int updateData(String updateSql, List<Object> params) throws Exception{
int result = -1;
PreparedStatement ps = conn.prepareStatement(updateSql);
for (int i = 0; i < params.size(); i++) {
ps.setObject(i+1, params.get(i));
}
result = ps.executeUpdate();
return result;
}
public ResultSet selectData(String selectSql, List<Object> params) throws Exception{
ResultSet rs = null;
PreparedStatement ps = conn.prepareStatement(selectSql);
if(params != null) {
for (int i = 0; i < params.size(); i++) {
ps.setObject(i+1, params.get(i));
}
}
rs = ps.executeQuery();
return rs;
}
}
UserDAO.java
package com.zfh;
public class UserDAO extends DAO {
}
DBUitl.java
package com.zfh.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBUtil {
private static final String DB_DRIVER = "com.mysql.jdbc.Driver";
private static final String DB_URL = "jdbc:mysql://localhost:3306/curdtestdb";
private static final String DB_USER = "root";
private static final String DB_PWD = "root";
private Connection conn = null;
public DBUtil() {
try {
Class.forName(DB_DRIVER);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
try {
conn = DriverManager.getConnection(DB_URL, DB_USER, DB_PWD);
} catch (SQLException e) {
e.printStackTrace();
}
}
public Connection getConn() {return conn;}
public void close() {
if (conn!=null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
App.java
package com.zfh;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import com.zfh.entity.User;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args )
{
// testInsertData();
// testUpdateData();
// testDeleteData();
testeSelectData();
}
public static void testUpdateData() {
UserDAO userDAO = new UserDAO();
String sql = "update t_user set name = ?, gender = ?,bir = ?, score = ? where id = ?";
// 两种优雅的方式对list进行赋值
List<Object> params = new ArrayList<Object>(){
{
add("克林丰华");
add("女");
add("2000-10-10");
add(85);
add(12004);
}
};
List<Object> params2 = Arrays.asList(12005,"皮特丰华","男","1999-09-09",98);
try {
int result = userDAO.updateData(sql, params);
System.out.println("有"+result+"条记录修改");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void testDeleteData() {
UserDAO userDAO = new UserDAO();
String sql = "delete from t_user where id = ?";
// 两种优雅的方式对list进行赋值
List<Object> params = new ArrayList<Object>(){
{
// add("克林丰华");
// add("女");
// add("2000-10-10");
// add(85);
add(12004);
}
};
// List<Object> params2 = Arrays.asList(12005,"皮特丰华","男","1999-09-09",98);
try {
int result = userDAO.updateData(sql, params);
System.out.println("有"+result+"条记录被删除");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void testInsertData()
{
UserDAO userDAO = new UserDAO();
String sql = "insert into t_user values(?,?,?,?,?)";
// 两种优雅的方式对list进行赋值
List<Object> params = new ArrayList<Object>(){
{
add(12004);
add("刘丰华");
add("男");
add("2000-10-10");
add(95);
}
};
List<Object> params2 = Arrays.asList(12005,"皮特丰华","男","1999-09-09",98);
try {
int result = userDAO.updateData(sql, params2);
System.out.println("有"+result+"条记录入库");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void testeSelectData() {
UserDAO userDAO = new UserDAO();
String sql = "select * from t_user";
List<User> users = new ArrayList<>();
try {
ResultSet rs = userDAO.selectData(sql, null);
while (rs.next()) {
User u = new User();
u.setId(rs.getString(1));
u.setName(rs.getString(2));
u.setGender(rs.getString(3));
u.setBir(rs.getDate(4));
u.setScore(rs.getInt(5));
users.add(u);
}
System.out.println("有"+users.size()+"条记录被查询到");
// System.out.println(users);
for (User user : users) {
System.out.println(user);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
AppTest.java
package com.zfh;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
/**
* Unit test for simple App.
*/
public class AppTest
extends TestCase
{
/**
* Create the test case
*
* @param testName name of the test case
*/
public AppTest( String testName )
{
super( testName );
}
/**
* @return the suite of tests being tested
*/
public static Test suite()
{
return new TestSuite( AppTest.class );
}
/**
* Rigourous Test :-)
*/
public void testApp()
{
assertTrue( true );
}
}
测试时注意事项
- 观察结果的位置：控制台
- main可以跑，junit也可以跑
- 适当设置开关，进行异常检查