struts+json
tips:注意 struts.xml配置， json-default 及引入 struts2-json-plugin-2.1.8.1.jar 包
1、json基础知识
JSON(JavaScript Object Notation)是一种轻量级的数据格式，采用完全独立于语言的文本格式，是理想的数据交换格式。同时，JSON是Javascript原生格式，这意 味着在javascript中处理JSON数据不需要任何特殊的API或工具包，而且效率非常高。
JSON的结构如下：
- “名称/值”对的集合（A collection of name/value pairs）。不同的语言中，它被理解为对象（object），纪录（record），结构（struct），字典（dictionary），哈希表（hash table），有键列表（keyed list），或者关联数组 （associative array）。
- 值的有序列表（An ordered list of values）。在大部分语言中，它被理解为数组（array）
一个标准的json格式：
{"name":"jifeng","company":"taobao"}
2.json的解析
json的解析方法共有两种：1. eval() ; 2.JSON.parse() ; 3.evalJSON()。具体使用方法如下:
var jsonstr = ‘{"name":"jifeng","company":"taobao"}‘;
//eval function
var evalJson = eval(‘(‘ + jsonstr + ‘)‘);
// JSON.parse function
var JSONParseJson = JSON.parse(jsonstr);
//这个引入property.js
var obj = jsonstr.evalJSON();
3.struts2的json响应的param类型 param name=" XX "
root：只包含xx对象excludeProperties ：除了xx之外的集合includeProperties ： 包含xx的集合 wrapPrefix ：json结果开头添加xx(比如<paramname="wrapPrefix">[</param>) wrapSuffix ：同上，只不过是结尾 ignoreHierarchy ：转化时是否忽略继承关系true/false enumAsBean : 是否将枚举当做一个bean处理 enableGZIP ：是否支持gzip压缩输出 noCache ：是否缓存 excludeNullProperties ： 是否转化输出 null值 statusCode ：设置响应代号比如 304 callbackParameter : JSONP跨域访问的回调设置 contentType ： 输出类型
4.fastjson 实例
实体类：
package com.pxj.fastjson.entity;
public class Student {
private int id;
private String name;
private int age;
/**
* 默认的构造方法必须不能省，不然不能解析
*/
public Student(){
}
public Student(int id,String name,int age) {
this.id = id;
this.name = name;
this.age = age;
}
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;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}
package com.pxj.fastjson.entity;
import java.util.List;
public class Teacher {
private int id;
private String name;
private List<Student> students;
/**
* 默认的构造方法必须不能省，不然不能解析
*/
public Teacher() {
}
public Teacher(int id,String name) {
this.id = id;
this.name = name;
}
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 List<Student> getStudents() {
return students;
}
public void setStudents(List<Student> students) {
this.students = students;
}
@Override
public String toString() {
return "Teacher [id=" + id + ", name=" + name + ", mStudents="
+ students + "]";
}
}
测试类:
package com.pxj.fastjson.demo;
import java.util.ArrayList;
import java.util.List;
import org.junit.Test;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.alibaba.fastjson.serializer.SimplePropertyPreFilter;
import com.pxj.fastjson.entity.Student;
import com.pxj.fastjson.entity.Teacher;
public class Demo {
@Test
public void test1() {
Student student = new Student(0, "Aaron", 24);
System.out.println(JSON.toJSONString(student));
}
//{"age":24,"id":0,"name":"Aaron"}
@Test
public void test2() {
List<Student> students = new ArrayList<Student>();
for (int i = 0; i < 5; i++) {
Student stu = new Student(i, "Student" + i, 18 + i);
students.add(stu);
}
System.out.println(JSON.toJSONString(students));
}
@Test
public void test3() {
List<Teacher> teaList = new ArrayList<Teacher>();
for (int i = 0; i < 10; i++) {
Teacher teacher = new Teacher(i, "Teacher " + i);
List<Student> stus = new ArrayList<Student>();
for (int j = 0; j < 4; j++) {
Student s = new Student(j, "Student" + j, 18 + j);
stus.add(s);
}
teacher.setStudents(stus);
teaList.add(teacher);
}
String jsonTeach = JSON.toJSONString(teaList);
System.out.println("fastjson = " + jsonTeach);
}
// 按照标准的json 格式输出
@Test
public void test4() {
Student student = new Student(0, "Aaron", 24);
System.out.println(JSON.toJSONString(student, true));
}
// 实体类中的某个字段或某几个不进行解析呢
@Test
public void test5() {
List<Student> students = new ArrayList<Student>();
for (int i = 0; i < 5; i++) {
Student stu = new Student(i, "Student" + i, 18 + i);
students.add(stu);
}
SimplePropertyPreFilter filter = new SimplePropertyPreFilter(Student.class, "id", "age");
String jsonStu = JSON.toJSONString(students, filter);
System.out.println(jsonStu);
}
//反序列化主要使用的是JSON.parseObject(str,class); 它就能把我们的str 转化为class 类型的对象，当然还有更复杂的对象
@Test
public void test6() {
List<Student> students = new ArrayList<Student>();
for (int i = 0; i < 5; i++) {
Student stu = new Student(i, "Student" + i, 18 + i);
students.add(stu);
}
String jsonStu = JSON.toJSONString(students);
List<Student> stu =JSON.parseObject(jsonStu, new TypeReference<List<Student>>(){});
for(int i=0;i<stu.size();i++)
{
System.out.println(stu.get(i));
}
}
}
5. struts+json实例
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>获取</title>
<script type="text/javascript" src="js/jquery-1.4.3.js">
</script>
<script type="text/javascript">
function loadInfo() {
$("#info").load("loadInfo");
}
</script>
</head>
<body>
<input type="button" value="获取" id="btnGet" onclick="loadInfo()" />
<div id="info"></div>
</body>
</html>
comment.java
package com.pxj.entity;
public class Comment {
private long id;
private String nickname;
private String content;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getNickname() {
return nickname;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
}
InfoAction.java
package com.pxj.action;
import java.util.ArrayList;
import java.util.List;
import org.apache.struts2.json.annotations.JSON;
import com.pxj.entity.Comment;
public class InfoAction {
private static final long serialVersionUID = 1359090410097337654L;
private List<Comment> comments = new ArrayList<Comment>();
//没getter and setter方法的属性不会被串行化到JSON
@SuppressWarnings("unused")
private String title;
//！！！使用transient修饰的属性也会被串行化到JSON
private transient String content;
public String loadInfo() {
title="123木头人";
content="你是木头人，哈哈。";
loadComments();
return "success";
}
/**
* 加载留言信息
*/
private void loadComments() {
Comment com1 = new Comment();
com1.setContent("很不错嘛");
com1.setId(1);
com1.setNickname("纳尼");
Comment com2 = new Comment();
com2.setContent("哟西哟西");
com2.setId(2);
com2.setNickname("小强");
comments.add(com1);
comments.add(com2);
}
//为了使content对象不被串行化到JSON，在不能舍弃其getter setter方法的时候，我们可以这样在content的getter方法上面加上注解：@JSON(serialize=false)
@JSON(serialize=false)
public List<Comment> getComments() {
return comments;
}
public void setComments(List<Comment> comments) {
this.comments = comments;
}
public static long getSerialversionuid() {
return serialVersionUID;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
}
struts.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
<package name="default" namespace="/" extends="json-default">
<action name="loadInfo" class="com.pxj.action.InfoAction" method="loadInfo">
<result name="success" type="json"></result>
</action>
</struts>
时间： 2024-10-25 09:30:08