json-lib的应用

阳光穿透心脏的1/2处 2022-05-28 12:47 99阅读 0赞

# json-lib的应用 #

## 一、概述 ##

apache提供的json-lib小工具，它可以方便的使用Java语言来创建JSON字符串。也可以把JavaBean转换成JSON字符串。

## 二、核心类 ##

在json-lib中只有两个核心类：

1， JSONObject；

2，JSONArray；

## 三、JSONObject ##

JSONObject类本身是一个Map

### 用法1：当map用 ###

Java Code

<table style="font-family:Consolas, 'Courier New';font-size:12px;vertical-align:text-top;line-height:15px;"> 
 <tbody> 
  <tr> 
   <td style="color:#008284;background-color:#e3e3e3;vertical-align:text-top;"> 
    <div style="margin:7px;text-align:right;white-space:nowrap;">
      1 
     <br>2 
     <br>3 
     <br>4 
     <br>5 
     <br>6 
     <br>7 
     <br> 
    </div></td> 
   <td style="background-color:#008284;padding:1px;"> 
    <div style="border:1px #008284 solid;"></div></td> 
   <td style="background-color:#efefef;width:100%;vertical-align:text-top;color:#000000;"> 
    <div style="margin:7px;">
      JSONObject&nbsp;jo&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;JSONObject(); 
     <br>jo.put( 
     <span style="color:#800000;">"name"</span>,&nbsp; 
     <span style="color:#800000;">"zhangSan"</span>); 
     <br>jo.put( 
     <span style="color:#800000;">"age"</span>,&nbsp; 
     <span style="color:#800000;">"18"</span>); 
     <br>jo.put( 
     <span style="color:#800000;">"sex"</span>,&nbsp; 
     <span style="color:#800000;">"male"</span>); 
     <br>System.out.println(jo.toString()); 
     <br> 
     <br>结果：&nbsp;{ 
     <span style="color:#800000;">"name"</span>:&nbsp; 
     <span style="color:#800000;">"zhangSan"</span>,&nbsp; 
     <span style="color:#800000;">"age"</span>:&nbsp; 
     <span style="color:#800000;">"18"</span>,&nbsp; 
     <span style="color:#800000;">"sex"</span>:&nbsp; 
     <span style="color:#800000;">"male"</span>} 
    </div></td> 
  </tr> 
 </tbody> 
</table>

### 用法2：把Javabean转化成json ###

Java Code

### 用法3：把map转换成json ###

Java Code

<table style="font-family:Consolas, 'Courier New';font-size:12px;vertical-align:text-top;line-height:15px;"> 
 <tbody> 
  <tr> 
   <td style="color:#008284;background-color:#e3e3e3;vertical-align:text-top;"> 
    <div style="margin:7px;text-align:right;white-space:nowrap;">
      1 
     <br>2 
     <br>3 
     <br>4 
     <br>5 
     <br>6 
     <br>7 
     <br>8 
     <br> 
    </div></td> 
   <td style="background-color:#008284;padding:1px;"> 
    <div style="border:1px #008284 solid;"></div></td> 
   <td style="background-color:#efefef;width:100%;vertical-align:text-top;color:#000000;"> 
    <div style="margin:7px;">
      Map&nbsp;map&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;HashMap(); 
     <br>map.put( 
     <span style="color:#800000;">"name"</span>,&nbsp; 
     <span style="color:#800000;">"wangWu"</span>); 
     <br>map.put( 
     <span style="color:#800000;">"age"</span>,&nbsp; 
     <span style="color:#800000;">"81"</span>); 
     <br>map.put( 
     <span style="color:#800000;">"sex"</span>,&nbsp; 
     <span style="color:#800000;">"male"</span>); 
     <br> 
     <br>JSONObject&nbsp;jo&nbsp;=&nbsp;JSONObject.fromObject(map); 
     <br>System.out.println(jo.toString()); 
     <br> 
    </div></td> 
  </tr> 
 </tbody> 
</table>

### 用法4：把xml转换成json，需要导入xom-1.1.jar ###

Java Code

<table style="font-family:Consolas, 'Courier New';font-size:12px;vertical-align:text-top;line-height:15px;"> 
 <tbody> 
  <tr> 
   <td style="color:#008284;background-color:#e3e3e3;vertical-align:text-top;"> 
    <div style="margin:7px;text-align:right;white-space:nowrap;">
      1 
     <br>2 
     <br>3 
     <br>4 
     <br>5 
     <br> 
    </div></td> 
   <td style="background-color:#008284;padding:1px;"> 
    <div style="border:1px #008284 solid;"></div></td> 
   <td style="background-color:#efefef;width:100%;vertical-align:text-top;color:#000000;"> 
    <div style="margin:7px;"> 
     <span style="color:#8000ff;">String</span>&nbsp;xml&nbsp;=&nbsp; 
     <span style="color:#800000;">"&lt;person&gt;&lt;name&gt;zhaoLiu&lt;/name&gt;&lt;age&gt;59&lt;/age&gt;&lt;sex&gt;female&lt;/sex&gt;&lt;/person&gt;"</span>; 
     <br>XMLSerializer&nbsp;serial&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;XMLSerializer(); 
     <br>JSONObject&nbsp;jo&nbsp;=&nbsp;(JSONObject)serial.read(xml); 
     <br>System.out.println(jo.toString()); 
     <br> 
    </div></td> 
  </tr> 
 </tbody> 
</table>

## 四、JSONArray ##

JSONArray本身是一个List

### 用法1：当成List用 ###

Java Code

<table style="font-family:Consolas, 'Courier New';font-size:12px;vertical-align:text-top;line-height:15px;"> 
 <tbody> 
  <tr> 
   <td style="color:#008284;background-color:#e3e3e3;vertical-align:text-top;"> 
    <div style="margin:7px;text-align:right;white-space:nowrap;">
      1 
     <br>2 
     <br>3 
     <br>4 
     <br>5 
     <br>6 
     <br>7 
     <br>8 
     <br> 
    </div></td> 
   <td style="background-color:#008284;padding:1px;"> 
    <div style="border:1px #008284 solid;"></div></td> 
   <td style="background-color:#efefef;width:100%;vertical-align:text-top;color:#000000;"> 
    <div style="margin:7px;">
      JSONArray&nbsp;ja&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;JSONArray(); 
     <br>Person&nbsp;p1&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;Person( 
     <span style="color:#800000;">"zhangSan"</span>,&nbsp; 
     <span style="color:#ff0000;">18</span>,&nbsp; 
     <span style="color:#800000;">"male"</span>); 
     <br>Person&nbsp;p2&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;Person( 
     <span style="color:#800000;">"liSi"</span>,&nbsp; 
     <span style="color:#ff0000;">23</span>,&nbsp; 
     <span style="color:#800000;">"female"</span>); 
     <br>ja.add(p1); 
     <br>ja.add(p2); 
     <br> 
     <br>System.out.println(ja.toString()); 
     <br> 
    </div></td> 
  </tr> 
 </tbody> 
</table>

### 用法2：把list转换成JSONArray ###

Java Code

<table style="font-family:Consolas, 'Courier New';font-size:12px;vertical-align:text-top;line-height:15px;"> 
 <tbody> 
  <tr> 
   <td style="color:#008284;background-color:#e3e3e3;vertical-align:text-top;"> 
    <div style="margin:7px;text-align:right;white-space:nowrap;">
      1 
     <br>2 
     <br>3 
     <br>4 
     <br>5 
     <br>6 
     <br>7 
     <br>8 
     <br>9 
     <br>10 
     <br> 
    </div></td> 
   <td style="background-color:#008284;padding:1px;"> 
    <div style="border:1px #008284 solid;"></div></td> 
   <td style="background-color:#efefef;width:100%;vertical-align:text-top;color:#000000;"> 
    <div style="margin:7px;">
      Person&nbsp;p1&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;Person( 
     <span style="color:#800000;">"zhangSan"</span>,&nbsp; 
     <span style="color:#ff0000;">18</span>,&nbsp; 
     <span style="color:#800000;">"male"</span>); 
     <br>Person&nbsp;p2&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;Person( 
     <span style="color:#800000;">"liSi"</span>,&nbsp; 
     <span style="color:#ff0000;">23</span>,&nbsp; 
     <span style="color:#800000;">"female"</span>); 
     <br>List&lt;Person&gt;&nbsp;list&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;ArrayList&lt;Person&gt;(); 
     <br>list.add(p1); 
     <br>list.add(p2); 
     <br> 
     <br>JSONArray&nbsp;ja&nbsp;=&nbsp;JSONArray.fromObject(list); 
     <br> 
     <br>System.out.println(ja.toString()); 
     <br> 
    </div></td> 
  </tr> 
 </tbody> 
</table>

### 用法3：把数组转换成JSONArray ###

Java Code

<table style="font-family:Consolas, 'Courier New';font-size:12px;vertical-align:text-top;line-height:15px;"> 
 <tbody> 
  <tr> 
   <td style="color:#008284;background-color:#e3e3e3;vertical-align:text-top;"> 
    <div style="margin:7px;text-align:right;white-space:nowrap;">
      1 
     <br>2 
     <br>3 
     <br>4 
     <br>5 
     <br>6 
     <br>7 
     <br>8 
     <br> 
    </div></td> 
   <td style="background-color:#008284;padding:1px;"> 
    <div style="border:1px #008284 solid;"></div></td> 
   <td style="background-color:#efefef;width:100%;vertical-align:text-top;color:#000000;"> 
    <div style="margin:7px;">
      Person&nbsp;p1&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;Person( 
     <span style="color:#800000;">"zhangSan"</span>,&nbsp; 
     <span style="color:#ff0000;">18</span>,&nbsp; 
     <span style="color:#800000;">"male"</span>); 
     <br>Person&nbsp;p2&nbsp;=&nbsp; 
     <span style="color:#0000ff;">new</span>&nbsp;Person( 
     <span style="color:#800000;">"liSi"</span>,&nbsp; 
     <span style="color:#ff0000;">23</span>,&nbsp; 
     <span style="color:#800000;">"female"</span>); 
     <br>Person[]&nbsp;persons&nbsp;=&nbsp;{p1,&nbsp;p2}; 
     <br> 
     <br>JSONArray&nbsp;ja&nbsp;=&nbsp;JSONArray.fromObject(persons); 
     <br> 
     <br>System.out.println(ja.toString()); 
     <br> 
    </div></td> 
  </tr> 
 </tbody> 
</table>

## 五、拓展 ##

服务器发送过来JSON字符串后，客户端需要对其进行解析。这时客户端需要使用eval()方法对JSON字符串进行执行！但要注意，eval()方法在执行JSON时，必须把JSON字符串使用一对圆括号括起来。

Java Code

<table style="font-family:Consolas, 'Courier New';font-size:12px;vertical-align:text-top;line-height:15px;"> 
 <tbody> 
  <tr> 
   <td style="color:#008284;background-color:#e3e3e3;vertical-align:text-top;"> 
    <div style="margin:7px;text-align:right;white-space:nowrap;">
      1 
     <br>2 
     <br>3 
     <br>4 
     <br> 
    </div></td> 
   <td style="background-color:#008284;padding:1px;"> 
    <div style="border:1px #008284 solid;"></div></td> 
   <td style="background-color:#efefef;width:100%;vertical-align:text-top;color:#000000;"> 
    <div style="margin:7px;">
      var&nbsp;json&nbsp;=&nbsp; 
     <span style="color:#800000;">"{\"</span>name\ 
     <span style="color:#800000;">":\"</span>zhangSan\ 
     <span style="color:#800000;">",&nbsp;\"</span>age\ 
     <span style="color:#800000;">":\"</span>18\ 
     <span style="color:#800000;">",&nbsp;\"</span>sex\ 
     <span style="color:#800000;">":\"</span>male\ 
     <span style="color:#800000;">"}"</span>; 
     <br>var&nbsp;person&nbsp;=&nbsp;eval( 
     <span style="color:#800000;">"("</span>&nbsp;+&nbsp;json&nbsp;+&nbsp; 
     <span style="color:#800000;">")"</span>); 
     <br>alert(person.name&nbsp;+&nbsp; 
     <span style="color:#800000;">",&nbsp;"</span>&nbsp;+&nbsp;person.age&nbsp;+&nbsp; 
     <span style="color:#800000;">",&nbsp;"</span>&nbsp;+&nbsp;person.sex); 
     <br> 
    </div></td> 
  </tr> 
 </tbody> 
</table>