Java中GET请求与POST请求，前端传参与后端接收实例

此示例以代码方式展现，可直接结合controller层每个接口上方注释与其接口传递参数方式理解！

前端传参直接就以apiPost工具来代替

apiPost调用后端接口几种方式

代码：

controller层：

package com.chensir.ceshi.controller;

import com.chensir.ceshi.entity.User;
import com.chensir.ceshi.service.GetAndPostService;
import com.chensir.handler.Result;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;

@RestController
@RequestMapping("/testGetAndPost")
public class GetAndPostController {

    @Resource
    private GetAndPostService getAndPostService;

    /**
     * 1、可查询全部（什么都不传）：http://localhost:8088/testGetAndPost/select1
     * 2、body json方式  值传不过来
     * 3、可 ？拼接（query）：http://localhost:8088/testGetAndPost/select1?sex=男
     * 4、body中form-data 值能传过来 可以查询 x-www-form-urlencoded 值传不过来 不能查询
     *
     */
    @GetMapping("/select1")
    public Result<Object> selectUser(User user) {
        List<User> userList= getAndPostService.selectUser(user);
        return Result.ok(userList);
    }

    /**
     * 1、查询全部（什么都不传）提示错误请求：http://localhost:8088/testGetAndPost/select2
     * 2、body json方式：可以查询
     * 3、？拼接（query）提示错误请求：http://localhost:8088/testGetAndPost/select1?sex=男
     * 4、body中form-data、x-www-form-urlencoded 提示错误请求
     *
     */
    @GetMapping("/select2")
    public Result<Object> selectUser1(@RequestBody User user) {
        List<User> userList= getAndPostService.selectUser(user);
        return Result.ok(userList);
    }

    /**
     * 1、body json方式：值传不过来 查询为空
     * 3、？拼接（query）可以查询：http://localhost:8088/testGetAndPost/select1?name=张三
     * 4、body中form-data：可以查询; x-www-form-urlencoded：值传不过来 查询为空
     *
     */
    @GetMapping("/select3")
    public Result<Object> selectUser2(String name) {
        List<User> userList= getAndPostService.selectUserByName(name);
        return Result.ok(userList);
    }

    /**
     * 1、body json方式：提示错误请求
     * 3、？拼接（query）可以查询：http://localhost:8088/testGetAndPost/select1?name=张三
     * 4、body中form-data：可以查询; x-www-form-urlencoded：提示错误请求
     *
     */
    @GetMapping("/select4")
    public Result<Object> selectUser3(@RequestParam String name) {
        List<User> userList= getAndPostService.selectUserByName(name);
        return Result.ok(userList);
    }

    /**
     * 1、只能以这样的方式：http://localhost:8088/testGetAndPost/selectUser/张三
     *
     */
    @GetMapping("/selectUser/{name}")
    public Result<Object> selectUser4(@PathVariable("name") String name) {
        List<User> userList= getAndPostService.selectUserByName(name);
        return Result.ok(userList);
    }

    /**
     * 和select3一样
     *
     */
    @GetMapping("/select5")
    public Result<Object> selectUser5(String name,Integer age) {
        List<User> userList= getAndPostService.selectUserByName1(name,age);
        return Result.ok(userList);
    }

    /**
     * 和select4一样
     *
     */
    @GetMapping("/select6")
    public Result<Object> selectUser6(@RequestParam("name") String name,@RequestParam("age") Integer age) {
        List<User> userList= getAndPostService.selectUserByName1(name,age);
        return Result.ok(userList);
    }

    /**
     * 1、只能以这样的方式：http://localhost:8088/testGetAndPost/selectUser/张三/18
     *
     */
    @GetMapping("/selectUser/{name}/{age}")
    public Result<Object> selectUser7(@PathVariable("name") String name,@PathVariable("age") Integer age) {
        List<User> userList= getAndPostService.selectUserByName1(name,age);
        return Result.ok(userList);
    }

    /**
     * 1、body json方式：值传不过来
     * 3、？拼接（query）值能传来，能新增：http://localhost:8088/testGetAndPost/select1?name=张三&age=18
     * 4、body中form-data、x-www-form-urlencoded：值都能传来，都可以新增
     *
     */
    @PostMapping("/add1")
    public Result<Object> addUser(User user){
        String msg=getAndPostService.addUser(user);
        return Result.ok(msg);
    }

    /**
     * 只能以body json
     *
     */
    @PostMapping("/add2")
    public Result<Object> addUser1(@RequestBody User user){
        String msg=getAndPostService.addUser(user);
        return Result.ok(msg);
    }

    /**
     * 1、body json方式：值传不过来
     * 3、？拼接（query）值能传来，能新增：http://localhost:8088/testGetAndPost/select1?name=张三
     * 4、body中form-data、x-www-form-urlencoded：值都能传来，都可以新增
     *
     */
    @PostMapping("/add3")
    public Result<Object> addUser2(@RequestParam("name") String name){
        String msg=getAndPostService.addUserName(name);
        return Result.ok(msg);
    }

    /**
     * 只能以 http://localhost:8088/testGetAndPost/selectUser/张三
     *
     */
    @PostMapping("/add4/{name}")
    public Result<Object> addUser3(@PathVariable("name") String name){
        String msg=getAndPostService.addUserName(name);
        return Result.ok(msg);
    }
}

service层：

public interface GetAndPostService {
    List<User> selectUser(User user);

    List<User> selectUserByName(String name);

    List<User> selectUserByName1(String name, Integer age);

    String addUser(User user);

    String addUserName(String name);
}

@Service
public class GetAndPostServiceImpl implements GetAndPostService {

    @Resource
    private GetAndPostMapper getAndPostMapper;

    @Override
    public List<User> selectUser(User user) {
        System.out.println(user.getName());
        return getAndPostMapper.selectUserList(user);
    }

    @Override
    public List<User> selectUserByName(String name) {
        return getAndPostMapper.selectUserByName(name);
    }

    @Override
    public List<User> selectUserByName1(String name, Integer age) {
        return getAndPostMapper.selectUserByName1(name,age);
    }

    @Override
    public String addUser(User user) {
        if (user==null){
            return "user为空";
        }
        int insert = getAndPostMapper.insert(user);
        return insert>0?"ok":"false";
    }

    @Override
    public String addUserName(String name) {
        if (name==null){
            return "name为空";
        }
        User user= User.builder()
                .name(name)
                .build();
        int insert = getAndPostMapper.insert(user);
        return insert>0?"ok":"false";
    }
}

mapper层：

public interface GetAndPostMapper extends BaseMapper<User> {

    List<User> selectUserList(@Param("query") User user);

    List<User> selectUserByName(String name);

    List<User> selectUserByName1(String name, Integer age);
}

xml：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.chensir.ceshi.mapper.GetAndPostMapper">

    <select id="selectUserList" resultType="com.chensir.ceshi.entity.User">
        select * from user
        where 1=1
        <if test="query.name != null and query.name != ''">
            and name = #{query.name}
        </if>
        <if test="query.age != null">
            and age = #{query.age}
        </if>
        <if test="query.sex != null and query.sex != ''">
            and sex = #{query.sex}
        </if>
    </select>
    <select id="selectUserByName" resultType="com.chensir.ceshi.entity.User">
        select * from user where name=#{name}
    </select>
    <select id="selectUserByName1" resultType="com.chensir.ceshi.entity.User">
        select * from user where name=#{name} and age=#{age}
    </select>
</mapper>