在开发中我们经常通过Gson来解析字符串，转化为所需要的Java对象。使用到它的地方很多，常用的几个方法总结如下：

1.字符串转实体类

public 
    
      T fromJson(JsonElement json,                      Class
     
       classOfT)           throws JsonSyntaxException
     
    

This method deserializes the Json read from the specified parse tree into an object of the specified type.

示例：

/**     * str ---> bean     */    private void str2bean(){        String str = "{'address':'xxx街xxx号','deptList':[{'employeeNum':'0','name':'部门0','task':'研发0'},{'employeeNum':'10','name':'部门1','task':'研发1'},{'employeeNum':'20','name':'部门2','task':'研发2'}],'name':'xxx公司'}";        Company cpy = new Gson().fromJson(str, Company.class);        Log.e("bean", cpy.toString());    }

2.实体类转字符串

String  toJson(Object src)

This method serializes the specified object into its equivalent Json representation.

示例：

/**     * bean ---> Json字符串     */    private void bean2str(){        Company cpy = new Company();        List
    
      list = new ArrayList
     
      ();        for(int i=0; i<3;i++){
                Department dpt = new Department();            dpt.setName("部门"+i);            dpt.setEmployeeNum("" + i * 10);            dpt.setTask("研发"+i);            list.add(dpt);        }        cpy.setName("xxx公司");        cpy.setAddress("xxx街xxx号");        cpy.setDeptList(list);        String str = new Gson().toJson(cpy);        Log.e("Company", str);    }    // {
   "address":"xxx街xxx号","deptList":[{
   "employeeNum":"0","name":"部门0","task":"研发0"},{
   "employeeNum":"10","name":"部门1","task":"研发1"},{
   "employeeNum":"20","name":"部门2","task":"研发2"}],"name":"xxx公司"}
     
    

3.字符串转JsonObject

JsonElement parse(String json)

Parses the specified JSON string into a parse tree

示例：

/**     * str ---> JsonObject     */    private void str2JsonObject() {        String str = "{'address':'xxx街xxx号','deptList':[{'employeeNum':'0','name':'部门0','task':'研发0'},{'employeeNum':'10','name':'部门1','task':'研发1'},{'employeeNum':'20','name':'部门2','task':'研发2'}],'name':'xxx公司'}";        JsonObject returnData = new JsonParser().parse(str).getAsJsonObject();        Log.e("JsonObject", returnData.toString());        //{
   "address":"xxx街xxx号","deptList":[{
   "employeeNum":"0","name":"部门0","task":"研发0"},{
   "employeeNum":"10","name":"部门1","task":"研发1"},{
   "employeeNum":"20","name":"部门2","task":"研发2"}],"name":"xxx公司"}    }

4.字符串转JsonArray

/**     * str ---> JsonArray     */    private void str2JsonArray() {        String arrStr = "[{'employeeNum':'0','name':'部门0','task':'研发0'},{'employeeNum':'10','name':'部门1','task':'研发1'},{'employeeNum':'20','name':'部门2','task':'研发2'}]";        JsonArray jsArray = new JsonParser().parse(arrStr).getAsJsonArray();        Log.e("JsonArray", jsArray.get(0).getAsJsonObject().get("name").getAsString());    }

5.字符串转JsonArray实体

/**     * str ---> JsonArrayBean     */    private void str2JsonArrayBean(){        String arrStr = "[{'employeeNum':'0','name':'部门0','task':'研发0'},{'employeeNum':'10','name':'部门1','task':'研发1'},{'employeeNum':'20','name':'部门2','task':'研发2'}]";        Gson gson = new Gson();        JsonParser parser = new JsonParser();        JsonArray jsArray = parser.parse(arrStr).getAsJsonArray();        ArrayList
    
      dptList = new ArrayList
     
      ();        for(JsonElement obj : jsArray){            Department dpt = gson.fromJson( obj , Department.class);            dptList.add(dpt);            Log.e("Dpt", dpt.toString());        }    }
     
    

涉及到的测试Java实体如下：

package com.example.gsontest;import java.util.List;public class Company {
        private String name;    private String address;    private List
    
      deptList;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getAddress() {        return address;    }    public void setAddress(String address) {        this.address = address;    }    public List
     
       getDeptList() {        return deptList;    }    public void setDeptList(List
      
        deptList) {        this.deptList = deptList;    }}
      
     
    

package com.example.gsontest;public class Department {    private String name;    private String employeeNum;    private String task;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getEmployeeNum() {        return employeeNum;    }    public void setEmployeeNum(String employeeNum) {        this.employeeNum = employeeNum;    }    public String getTask() {        return task;    }    public void setTask(String task) {        this.task = task;    }}