json

JSON小结【json-lib】

 

javabean:Address

 

package com.baebae.model;

public class Address
{
    private String city;
    private String district;
    private String street;
    private int no;

    getter/setter()...
}

 

 

JAVA--JSON互相转换：

 

【1】JAVA——>JSON

 

/**
     * <1> JAVA-->JSON
     * 单个对象Object-->JSONObject
     * 集合List/Array/Set----->JSONArray
     */
    @Test
    public void testObj2JSON() throws InterruptedException {
        // 1.bean---->json
        Address addr = new Address();
        addr.setCity("北京");
        addr.setDistrict("清河");
        addr.setStreet("安宁庄东路");
        addr.setNo(200);

        JSONObject jsonObj = JSONObject.fromObject(addr);
        System.err.println("____________jsonObj_______________");
        System.out.println(jsonObj);
        // 1.集合-->JSONArray
        Set<Address> set = new HashSet<Address>();
        Address[] addrArray = new Address[100];
        List<Address> list = new ArrayList<Address>();
        for(int i=0;i<10;i++){
            Address address = new Address();
            address.setCity("北京");
            address.setDistrict("清河");
            address.setStreet("安宁庄东路"+i+"号");
            address.setNo(200+i);

            list.add(address);
            addrArray[i]=address;
            set.add(address);
        }
        // 这里不能用JSONObject.fromObject(collection)
        JSONArray jsonList = JSONArray.fromObject(list);
        JSONArray jsonArray = JSONArray.fromObject(addrArray);
        JSONArray jsonSet = JSONArray.fromObject(set);

        // 打印结果
        Thread.sleep(3000);
        System.err.println("____________jsonList_______________");
        System.out.println(jsonList);
        Thread.sleep(3000);
        System.err.println("_____________jsonArray______________");
        System.out.println(jsonArray);
        Thread.sleep(3000);
        System.err.println("______________jsonSet_____________");
        System.out.println(jsonSet);
        Thread.sleep(3000);
    }

打印结果：

 

 

____________jsonObj_______________
{"city":"北京","district":"清河","no":200,"street":"安宁庄东路"}
____________jsonList_______________
[{"city":"北京","district":"清河","no":200,"street":"安宁庄东路0号"},{"city":"北京","district":"清河","no":201,"street":"安宁庄东路1号"},{"city":"北京","district":"清河","no":202,"street":"安宁庄东路2号"},{"city":"北京","district":"清河","no":203,"street":"安宁庄东路3号"},{"city":"北京","district":"清河","no":204,"street":"安宁庄东路4号"},{"city":"北京","district":"清河","no":205,"street":"安宁庄东路5号"},{"city":"北京","district":"清河","no":206,"street":"安宁庄东路6号"},{"city":"北京","district":"清河","no":207,"street":"安宁庄东路7号"},{"city":"北京","district":"清河","no":208,"street":"安宁庄东路8号"},{"city":"北京","district":"清河","no":209,"street":"安宁庄东路9号"}]
_____________jsonArray______________
[{"city":"北京","district":"清河","no":200,"street":"安宁庄东路0号"},{"city":"北京","district":"清河","no":201,"street":"安宁庄东路1号"},{"city":"北京","district":"清河","no":202,"street":"安宁庄东路2号"},{"city":"北京","district":"清河","no":203,"street":"安宁庄东路3号"},{"city":"北京","district":"清河","no":204,"street":"安宁庄东路4号"},{"city":"北京","district":"清河","no":205,"street":"安宁庄东路5号"},{"city":"北京","district":"清河","no":206,"street":"安宁庄东路6号"},{"city":"北京","district":"清河","no":207,"street":"安宁庄东路7号"},{"city":"北京","district":"清河","no":208,"street":"安宁庄东路8号"},{"city":"北京","district":"清河","no":209,"street":"安宁庄东路9号"},null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null]
______________jsonSet_____________
[{"city":"北京","district":"清河","no":207,"street":"安宁庄东路7号"},{"city":"北京","district":"清河","no":202,"street":"安宁庄东路2号"},{"city":"北京","district":"清河","no":200,"street":"安宁庄东路0号"},{"city":"北京","district":"清河","no":204,"street":"安宁庄东路4号"},{"city":"北京","district":"清河","no":205,"street":"安宁庄东路5号"},{"city":"北京","district":"清河","no":208,"street":"安宁庄东路8号"},{"city":"北京","district":"清河","no":209,"street":"安宁庄东路9号"},{"city":"北京","district":"清河","no":203,"street":"安宁庄东路3号"},{"city":"北京","district":"清河","no":206,"street":"安宁庄东路6号"},{"city":"北京","district":"清河","no":201,"street":"安宁庄东路1号"}]

  --------------------------------------------------------------------------------

 

【2】JSON---->JAVA

/**
     * <2> JSON-->JAVA
     * 1.如果字段名有错无法匹配，会发出警告；属性得到是null.
     * 2.转换：
     *  ->Object
     *      <1> 字符串封装成JSON 对象：【JSONObject.fromObject(jsonStr)】
     *      <2> JSON对象转换成Object:【(Address) JSONObject.toBean(jsonObject, Address.class)】
     *  ->Collection
     *      <1> 字符串封装成JSONArray 对象：【JSONArray.fromObject(jsonArrayStr)】
     *      <2> JSONArray对象转换成Java集合:【(List<Address>)JSONArray.toCollection(jsonArray, Address.class)】
     */
    @Test
    public void testJson2Java()  throws InterruptedException {
        // 1.JSON object
        String jsonStr = "{\"city\":\"北京\",\"district\":\"清河\",\"street\":\"安宁庄东路南口\",\"no\":500}";
        // 3.JSONArray
        String jsonArrayStr = "[{\"city\":\"北京\",\"district\":\"清河\",\"street\":\"安宁庄东路南口\",\"no\":500},{\"city\":\"北京\",\"district\":\"上地\",\"street\":\"安宁庄东路\",\"no\":300}]";

        JSONObject jsonObject = JSONObject.fromObject(jsonStr);
        JSONArray jsonArray = JSONArray.fromObject(jsonArrayStr);

        // JSONObject.toBean(jasonObject,Class): Bean;
        Address address  = (Address) JSONObject.toBean(jsonObject, Address.class);
        List<Address> list = (List<Address>)JSONArray.toCollection(jsonArray, Address.class);

        // 1.输出Object
        Thread.sleep(1000);
        System.out.println("District:"+address.getDistrict());
        // 2.输出Array
        Thread.sleep(1000);
        for(Address addr:list){
            System.out.println(addr.getCity()+"\t"+addr.getDistrict()+"\t"+addr.getStreet()+"\t"+addr.getNo());
        }
    }

 

打印结果：

District:清河
北京  清河  安宁庄东路南口 500
北京  上地  安宁庄东路   300

 

 

【总结】：

JSON————>JAVA:

        ->Object                                                                                      

    <1> 字符串封装成JSON 对象：【JSONObject.fromObject(jsonStr)】                                        

    <2> JSON对象转换成Object:【(Address) JSONObject.toBean(jsonObject, Address.class)】              

        ->Collection                                                                                  

    <1> 字符串封装成JSONArray 对象：【JSONArray.fromObject(jsonArrayStr)】                               

    <2> JSONArray对象转换成Java集合:【(List<Address>)JSONArray.toCollection(jsonArray, Address.class)】

 

JAVA————>JSON:

        Object：【JSONObject.fromObject(addr)】

      Collection：【JSONArray.fromObject(list)】

 

参考资料：

1.官方网站：http://sourceforge.net/projects/json-lib

2.所需jar包：

commons-beanutils-1.8.3.jar
commons-collections-3.2.1.jar
commons-lang-2.5.jar
commons-logging-1.1.1.jar
ezmorph-1.0.6.jar
json-lib-2.4-jdk15.jar