第四章：数据交互

json数据交互
客户端发送请求一共2种方式json回来
1.key value 原生js请求
2.json方式
html---------->Controller
以下有2种方式
1.请求json过渡到过滤器
2.过滤器如何快速返json

这个是通过url地址来传值

http://localhost:8080/TestSpringMvc/ajax/test1?empno=1&empname=2&sal=3

@Controller
@RequestMapping("/ajax")
public class AjaxController {
    
    /*
     * content-type:application/x-www-form-urlencoded=> 1.test(Integer empno, String empname, Double sal)
     * content-type:application/json => @RequestBody Employee e
     *     @RequestBody:解析json字符串，把请求数据拿出来，放在对象里
     *  
     */
    
    //http://localhost:8080/TestSpringMvc/ajax/test1?empno=1&empname=2&sal=3
    //test1 通过一个一个传递属性来获得
    @RequestMapping("/test1")
    public void test1(Integer empno,String empname,Double sal ,HttpServletResponse resp) {
        System.out.println(empno);
        System.out.println(empname);
        System.out.println(sal);
        try {
            resp.getWriter().append("{\"result\":true}");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

显示地址不一样

2.png

第二种方式这个是通过阿贾克斯来传,请求数据组装成（节深）字符串形式向Springmvc发送放到@RequestBody Employee e 字符串形式和解析出来放到这里


    
        com.fasterxml.jackson.core
        jackson-databind
        2.10.0





Insert title here

@Controller
@RequestMapping("/ajax")
public class AjaxController {
    
    /*
     * content-type:application/x-www-form-urlencoded=> 1.test(Integer empno, String empname, Double sal)
     * content-type:application/json => @RequestBody Employee e
     *     @RequestBody:解析json字符串，把请求数据拿出来，放在对象里
     *  
     */
    
    //http://localhost:8080/TestSpringMvc/ajax/test1?empno=1&empname=2&sal=3
    //test1 通过一个一个传递属性来获得
    @RequestMapping("/test1")
    public void test1(Integer empno,String empname,Double sal ,HttpServletResponse resp) {
        System.out.println(empno);
        System.out.println(empname);
        System.out.println(sal);
        try {
            resp.getWriter().append("{\"result\":true}");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    //test2 通过前端js框架组装字符串 到这里进行字符串解析 成为类获得值
    @RequestMapping("/test2")
    public void test(@RequestBody Employee e, HttpServletResponse resp)
    {
        
        System.out.println(e.getEmpno());
        System.out.println(e.getEmpname());
        System.out.println(e.getSal());
        
        try {
            resp.getWriter().append("{\"result\":true}");
        } catch (IOException ex) {
            // TODO Auto-generated catch block
            ex.printStackTrace();
        }
    }

}

2345截图20191111141812.png

数据已经传给Controller 数据如何通过controller传送给页面！

在SpringMvc有个处理，返回是一个对象或者一个集合在方法返回值上面加个
@RequestBody

    @RequestMapping("/test3")
    @ResponseBody
    public List test(@RequestBody Employee e)
    {
        System.out.println(e.getEmpno());
        System.out.println(e.getEmpname());
        System.out.println(e.getSal());
        
        List list = new ArrayList<>();
        
        Employee e1 = new Employee();
        e1.setEmpno(1);
        e1.setEmpname("jack");
        
        Employee e2 = new Employee();
        e2.setEmpno(2);
        e2.setEmpname("james");
        
        list.add(e1);
        list.add(e2);

        return list;
    }

**还是通过输入ajax地址返回来还是一个对象

3331194830.png

html---->controller springMVC
html向controller走的时候，是组装成json字符串过去的
html----controller 艾克寿司做的
StringMVC解析json字符串组装成对象放到控制器里，然后查询数据库，列表打印成json字符串，把列表打成json字符串发送到客户端来了调用了一个组件
@RequestBody SpringMvc
@ResponseBody json

如果一个controller下，都是响应ajax请求，@RestController = @Controller + @ResponseBody

2345截图20191111202911.png

如何通过字符串返回客户端

package com.fcx.bean;

import java.util.Date;

import com.fasterxml.jackson.annotation.JsonFormat;

public class Employee {
    
    private int empno;
    private String empname;
    @JsonFormat(pattern="yyyy-MM-dd HH:mm:ss",timezone="GMT+8")
    private Date hiredate;
    public int getEmpno() {
        return empno;
    }
    public void setEmpno(int empno) {
        this.empno = empno;
    }
    public String getEmpname() {
        return empname;
    }
    public void setEmpname(String empname) {
        this.empname = empname;
    }
    public Date getHiredate() {
        return hiredate;
    }
    public void setHiredate(Date hiredate) {
        this.hiredate = hiredate;
    }
}

@RestController
@RequestMapping("/ajax2")
public class AjaxController2 {
    
    /*
     * content-type:application/x-www-form-urlencoded=> 1.test(Integer empno, String empname, Double sal)
     * content-type:application/json => @RequestBody Employee e
     *     @RequestBody: 解析json字符串，把请求数据拿出来，放在对象里。
     *  
     */
    
    @RequestMapping("/test1")
    public List test(@RequestBody Employee e)
    {
        
        System.out.println(e.getEmpno());
        System.out.println(e.getEmpname());
        
        List list = new ArrayList<>();
        
        Employee e1 = new Employee();
        e1.setEmpno(1);
        e1.setEmpname("jack");
        e1.setHiredate(new Date());
        
        Employee e2 = new Employee();
        e2.setEmpno(2);
        e2.setEmpname("james");
        e2.setHiredate(java.sql.Date.valueOf("1987-01-01"));
        
        list.add(e1);
        list.add(e2);
        
        return list;
    }

}

22.png

用阿贾克斯文件上传





Insert title here

@Controller
@RequestMapping("/upload2")
public class UploadController2 {
    
    @RequestMapping("/upload")
    public void upload(String username, Date birthday, MultipartFile avatar, HttpServletResponse resp)
    {
        System.out.println("JAJAJAJAJA");
        System.out.println(username);
        System.out.println(birthday);
        System.out.println(avatar.getOriginalFilename());
        
        String newfilename = UUID.randomUUID().toString()+avatar.getOriginalFilename().substring(avatar.getOriginalFilename().lastIndexOf("."));
        
        File dest = new File("d:/images",newfilename);
            
        
        try {
            avatar.transferTo(dest);
        } catch (IllegalStateException | IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        
        try {
            resp.getWriter().append("{\"result\":true}");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

RESTFUl面向资源一种请求

restui面向资源的，你原来对比一下，现在请求url
get emp查询，set emp ，delete emp
，url加动词体现干啥，你不应该这样写面向资源方式写，你操作员工，你想查询所有员工 emps 配合请求方式get然后你想往这里面新增一个路径emps
只是提交方式post，我想用id查询员工信息 emp/员工编号101或者员工102更像他还是这一个资源
更新 put 删除101 delte 在这种架构下，面向资源，在url路径下不应该有资源配合请求方式

5.png

@RestController
public class RestFullController {
    
    @GetMapping("/emps")
    public List getEmps()
    {
        List list = new ArrayList<>();
        
        Employee e = new Employee();
        e.setEmpno(1);
        e.setEmpname("jack");
        e.setHiredate(new Date());
        
        Employee e2 = new Employee();
        e2.setEmpno(2);
        e2.setEmpname("james");
        e2.setHiredate(java.sql.Date.valueOf("1990-1-1"));
        
        list.add(e);
        list.add(e2);
        
        return list;
    }
    
    @PostMapping("/emps")
    public String addEmp(Employee e)
    {
        System.out.println(e.getEmpno());
        System.out.println(e.getEmpname());
        System.out.println(e.getHiredate());
        //add to database
        return "{\"result\":true}";
    }
    
    @GetMapping("/emp/{id}")
    public Employee getEmployee(@PathVariable int id)
    {
        System.out.println(id);
        return new Employee();
    }
    
    @DeleteMapping("/emp/{id}")
    public String deleteEmployee(@PathVariable int id)
    {
        System.out.println(id);
        return "{\"result\":true}";
    }
    
    @PutMapping("/emp/{id}")
    public String updateEmployee(@PathVariable int id, Employee e)
    {
        System.out.println(id);
        
        System.out.println(e.getEmpno());
        System.out.println(e.getEmpname());
        System.out.println(e.getHiredate());
        //add to database
        return "{\"result\":true}";
        
    }
    

}

加个过滤器

  
   
      HttpMethodFilter
      org.springframework.web.filter.HttpPutFormContentFilter
    
    
         HttpMethodFilter
         /*