完成分页获取用户信息api 11

1、前提约束

• 完成新增学生api

2、技术选型

• springmvc+spring+mybatis
• pagehelper

3、修改net.wanho.mapper.StudentMapper.java接口

新增query方法申明：

package net.wanho.mapper;

import net.wanho.entity.Student;
import java.util.List;

public interface StudentMapper {

    void add(Student student) throws Exception;
    void update(Student student) throws Exception;
    void delete(int id) throws Exception;
    void get(int id) throws Exception;
    List query() throws Exception;
}

4、修改net/wanho/mapper/StudentMapper.xml文件

新增update方法对应的sql：

    
    
        insert into t_student(name) values(#{name})
    
    
        update t_student set name=#{name} where id=#{id}
    
    
        delete from t_student where id=#{id}
    
    
        select * from t_student where id=#{id}
    

    
        select * from t_student
    

5、修改net.wanho.service.StudentServiceI.java接口

新增queryStudents方法申明：

package net.wanho.service;

import net.wanho.entity.Student;
import java.util.List;

public interface StudentServiceI {
    void addStudent(Student student)throws Exception;
    void updateStudent(Student student)throws Exception;
    void deleteStudent(int id)throws Exception;
    Student getStudent(int id)throws Exception;
    List queryStudents()throws Exception;
}

6、修改net.wanho.service.impl.StudentServiceImpl.java

新增queryStudents方法的实现：

package net.wanho.service.impl;

import net.wanho.entity.Student;
import net.wanho.mapper.StudentMapper;
import net.wanho.service.StudentServiceI;
import org.springframework.stereotype.Service;

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

@Service
public class StudentServiceImpl implements StudentServiceI {

    //注入StudentMapper
    @Resource
    private StudentMapper studentMapper;

    public void addStudent(Student student) throws Exception {
        studentMapper.add(student);
    }
    public void updateStudent(Student student) throws Exception {
        studentMapper.update(student);
    }
    public void deleteStudent(int id) throws Exception {
        studentMapper.delete(id);
    }

    public Student getStudent(int id) throws Exception {
        return studentMapper.get(id);
    }

    public List queryStudents() throws Exception {
        return studentMapper.query();
    }
}

7、修改net.wanho.controller.StudentController.java

创建queryStudents API入口：

package net.wanho.controller;

import com.alibaba.fastjson.JSONObject;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.github.pagehelper.PageInterceptor;
import net.wanho.entity.Student;
import net.wanho.service.StudentServiceI;
import org.springframework.stereotype.Controller;
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.ResponseBody;

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

@Controller
public class StudentController {

    @Resource
    private StudentServiceI studentService;

    @RequestMapping(value="/student/add",method = RequestMethod.GET)
    @ResponseBody
    public JSONObject addStudent(Student student)
    {
        JSONObject ret = new JSONObject();
        try {
            studentService.addStudent(student);
            ret.put("status",200);
            ret.put("msg","add success:"+student.getId());
        }
        catch(Exception e)
        {
            ret.put("status",100);
            ret.put("msg","add error");
            e.printStackTrace();
        }
        return ret;
    }

    @RequestMapping(value="/student/update",method = RequestMethod.GET)
    @ResponseBody
    public JSONObject updateStudent(Student student)
    {
        JSONObject ret = new JSONObject();
        try {
            studentService.updateStudent(student);
            ret.put("status",200);
            ret.put("msg","update ok");
        }
        catch(Exception e)
        {
            ret.put("status",100);
            ret.put("msg","update error");
            e.printStackTrace();
        }
        return ret;
    }

    @RequestMapping(value="/student/delete/{id}",method = RequestMethod.GET)
    @ResponseBody
    public JSONObject deleteStudent(@PathVariable("id") int id)
    {
        JSONObject ret = new JSONObject();
        try {
            studentService.deleteStudent(id);
            ret.put("status",200);
            ret.put("msg","delete ok");
        }
        catch(Exception e)
        {
            ret.put("status",100);
            ret.put("msg","delete error");
            e.printStackTrace();
        }
        return ret;
    }

    @RequestMapping(value="/student/get/{id}",method = RequestMethod.GET)
    @ResponseBody
    public JSONObject getStudent(@PathVariable("id") int id)
    {
        JSONObject ret = new JSONObject();
        try {
            Student student = studentService.getStudent(id);
            ret.put("status",200);
            ret.put("data",student);
        }
        catch(Exception e)
        {
            ret.put("status",100);
            ret.put("msg","get error");
            e.printStackTrace();
        }
        return ret;
    }

    @RequestMapping(value="/student/query",method = RequestMethod.GET)
    @ResponseBody
    public JSONObject queryStudents(int pageNum,int pageSize)
    {
        JSONObject ret = new JSONObject();
        try {
            PageHelper.startPage(pageNum,pageSize);
            List students = studentService.queryStudents();
            PageInfo pageInfo = new PageInfo(students);
            ret.put("status",200);
            ret.put("data",pageInfo);
        }
        catch(Exception e)
        {
            ret.put("status",100);
            ret.put("msg","query error");
            e.printStackTrace();
        }
        return ret;
    }
}

8、测试

打开mysql命令行以及浏览器，具体操作如下图所示：

测试分页获取用户信息

至此，我们完成了分页查询用户信息的api，并做了测试。