SpringBoot进阶之访问数据库（含源码）

本文介绍在Spring Boot基础下配置数据源和通过JdbcTemplate编写数据访问的示例。

简单介绍一下

@Controller：修饰class，用来创建处理http请求的对象

@RestController：Spring4之后加入的注解，原来在@Controller中返回json需要@ResponseBody来配合，如果直接用@RestController替代@Controller就不需要再配置@ResponseBody，默认返回json格式。

@RequestMapping：配置url映射

数据源配置

首先，为了连接数据库需要引入jdbc支持，在pom.xml中引入如下配置：

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

以MySQL数据库为例，先引入MySQL连接的依赖包，在pom.xml中加入：

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.21</version>
</dependency>

配置数据源信息

在application.yml配置数据源信息

spring:
datasource:
url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8
username: root
password: root
driver-class-name: com.mysql.jdbc.Driver

使用JdbcTemplate操作数据库

编写实体类Student.java

package com.javazhan.domain;

public class Student {
private int id ;
private String name ;
private int age ;
private String address ;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}

}

编写StudentService.java

package com.javazhan.service;

import java.util.List;

import com.javazhan.domain.Student;

public interface StudentService {

/**
* 新增一个学生
* @param student
*/
void create(Student student) ;

/**
* 根据id删除一个学生
* @param id
*/
void deleteById(int id) ;

/**
* 查出所有学生
* @return
*/
List<Student> getAllStudent() ;

/**
* 根据id查出学生
* @return
*/
Student getStudentById(int id) ;

/**
* 根据Id更新一个学生
*/
void updateStudentById(Student student) ;
}

编写实现类StudentServiceImpl.java

package com.javazhan.service.impl;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Service;

import com.javazhan.domain.Student;
import com.javazhan.service.StudentService;

@Service
public class StudentServiceImpl implements StudentService {

@Autowired
private JdbcTemplate jdbcTemplate  ;

@Override
public void create(Student student) {
// TODO Auto-generated method stub
jdbcTemplate.update("insert into student(name, age, address) value(?,?,?)", student.getName(), student.getAge(), student.getAddress()) ;
}

@Override
public void deleteById(int id) {
// TODO Auto-generated method stub
jdbcTemplate.update("delete from student where id = ?", id) ;
}

@Override
public List<Student> getAllStudent() {
// TODO Auto-generated method stub
return jdbcTemplate.query("select * from student", new RowMapper()
{
@Override
public Object mapRow(ResultSet rs, int rowNum) throws SQLException
{
Student student = new Student();
student.setId(rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
student.setAddress(rs.getString("address"));
return student;
}
}) ;
}

@Override
public Student getStudentById(int id) {
// TODO Auto-generated method stub
return (Student) jdbcTemplate.query("select * from student where id=?", new ResultSetExtractor() {
@Override
public Student extractData(ResultSet rs) throws SQLException {
while (rs.next()) {
Student student = new Student();
student.setId(rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
student.setAddress(rs.getString("address"));
return student ;
}
return null ;
}
}, id);
}

@Override
public void updateStudentById(Student student) {
// TODO Auto-generated method stub
jdbcTemplate.update("update student set name=?, age=?, address=? where id =?", student.getName(), student.getAge(), student.getAddress(),student.getId()) ;
}

}

我们尝试使用Spring MVC来实现一组对Student对象操作的RESTful API，配合注释详细说明在Spring MVC中如何映射HTTP请求、如何传参、如何编写单元测试。

请求类型	URL	功能说明
GET	/student	查询所有学生
POST	/student	新增一个学生
GET	/student/id	根据id查询一个学生
PUT	/student/id	根据id更新一个学生
DELETE	/student/id	根据id删除一个学生

编写StudentRestController .java

package com.javazhan.web.rest;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.javazhan.domain.Student;
import com.javazhan.service.StudentService;

@RestController
@RequestMapping(value="student")
public class StudentRestController {

@Autowired
private StudentService stuService ;
/**
* 查出所有学生
* @return
*/
@RequestMapping(value="/", method=RequestMethod.GET)
public List<Student> getAllStudent() {
return stuService.getAllStudent() ;
}

/**
* 根据id查出学生
* @return
*/
@RequestMapping(value="/{id}", method=RequestMethod.GET)
public Student getStudentById(@PathVariable Integer id) {
return stuService.getStudentById(id) ;
}

/**
* 根据id删除学生
* @return
*/
@RequestMapping(value="/{id}", method=RequestMethod.DELETE)
public String deleteById(@PathVariable Integer id) {
stuService.deleteById(id) ;
return "success" ;
}

/**
* 新增一个学生
* @return
*/
@RequestMapping(value="/", method=RequestMethod.POST)
public String create(@ModelAttribute Student student) {
stuService.create(student) ;
return "success" ;
}

/**
* 根据Id更新一个学生
* @return
*/
@RequestMapping(value="/", method=RequestMethod.PUT)
public String updateStudentById(@ModelAttribute Student student) {
stuService.updateStudentById(student) ;
return "success" ;
}
}

编写测试RestTest.java

package com.java.test;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.delete;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.MvcResult;
import org.springframework.test.web.servlet.RequestBuilder;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import com.javazhan.RunApplication;

@RunWith(SpringRunner.class)
@SpringBootTest(classes=RunApplication.class)
public class RestTest {
@Autowired
private WebApplicationContext context;

// mock api 模拟http请求
private MockMvc mvc;

@Before
public void setUp() throws Exception {
//集成Web环境测试（此种方式并不会集成真正的web环境，而是通过相应的Mock API进行模拟测试，无须启动服务器）
mvc = MockMvcBuilders.webAppContextSetup(context).build();
}
@Test
public void testUserController() throws Exception {
RequestBuilder request = null ;
MvcResult mvcResult = null ;
int status = 500 ;
// 新增学生
request = post("/student/").param("name", "李四")
.param("age", "20")
.param("address", "哈尔滨") ;
mvcResult = mvc.perform(request).andReturn() ;
status = mvcResult.getResponse().getStatus() ;
if(status==200) {
String content = mvcResult.getResponse().getContentAsString() ;
System.out.println("新增学生："+content) ;
}
// 查出所有学生
request = get("/student/") ;
mvcResult = mvc.perform(request).andReturn() ;
status = mvcResult.getResponse().getStatus() ;
if(status==200) {
String content = mvcResult.getResponse().getContentAsString() ;
System.out.println("查出所有学生："+content);
}
// 根据Id查询学生
request = get("/student/1") ;
mvcResult = mvc.perform(request).andReturn() ;
status = mvcResult.getResponse().getStatus() ;
if(status==200) {
String content = mvcResult.getResponse().getContentAsString() ;
System.out.println("根据Id查询学生："+content) ;
}

// 根据Id更新一个学生
request = put("/student/").param("id", "5")
.param("name", "李四5")
.param("age", "25")
.param("address", "哈尔滨5") ;
mvcResult = mvc.perform(request).andReturn() ;
status = mvcResult.getResponse().getStatus() ;
if(status==200) {
String content = mvcResult.getResponse().getContentAsString() ;
System.out.println("根据Id更新一个学生："+content) ;
}

// 根据id删除一个学生
request = delete("/student/6") ;
mvcResult = mvc.perform(request).andReturn() ;
status = mvcResult.getResponse().getStatus() ;
if(status==200) {
String content = mvcResult.getResponse().getContentAsString() ;
System.out.println("根据id删除一个学生："+content) ;
}

}
}

编写RunApplication.java

package com.javazhan;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class RunApplication {

public static void main(String[] args) {
SpringApplication.run(RunApplication.class, args) ;
}
}

源码下载

SpringBoot进阶之访问数据库（含源码）

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