Json转换利器Gson之实例五-实际开发中的特殊需求处理

前面四篇博客基本上可以满足我们处理的绝大多数需求,但有时项目中对json有特殊的格式规定.比如下面的json串解析:

[{"tableName":"students","tableData":[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 9:54:49 PM"},{"id":2,"name":"曹贵生","birthDay":"Jun 22, 2012 9:54:49 PM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 9:54:49 PM"}]},{"tableName":"teachers","tableData":[{"id":1,"name":"米老师","title":"教授"},{"id":2,"name":"丁老师","title":"讲师"}]}]

分析之后我们发现使用前面博客中用到的都不好处理上面的json串.请看本文是如何处理的吧:

实体类:

[java] view
plaincopy

import java.util.Date;

public class Student {

private int id;

private String name;

private Date birthDay;

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 Date getBirthDay() {

return birthDay;

}

public void setBirthDay(Date birthDay) {

this.birthDay = birthDay;

}

@Override

public String toString() {

return "Student [birthDay=" + birthDay + ", id=" + id + ", name="

+ name + "]";

}

}

[java] view
plaincopy

public class Teacher {

private int id;

private String name;

private String title;

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 String getTitle() {

return title;

}

public void setTitle(String title) {

this.title = title;

}

@Override

public String toString() {

return "Teacher [id=" + id + ", name=" + name + ", title=" + title

+ "]";

}

}

注意这里定义了一个TableData实体类:

[java] view
plaincopy

import java.util.List;

public class TableData {

private String tableName;

private List tableData;

public String getTableName() {

return tableName;

}

public void setTableName(String tableName) {

this.tableName = tableName;

}

public List getTableData() {

return tableData;

}

public void setTableData(List tableData) {

this.tableData = tableData;

}

}

测试类:

(仔细看将json转回为对象的实现,这里经过两次转化,第一次转回的结果是map不是我们所期望的对象,对map再次转为json后再转为对象,我引用的是Gson2.1的jar处理正常,好像使用Gson1.6的jar会报错,所以建议用最新版本)

[java] view
plaincopy

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import com.google.gson.Gson;

import com.google.gson.reflect.TypeToken;

public class GsonTest5 {

/**

* @param args

*/

public static void main(String[] args) {

// 对象转为Json-->start

Student student1 = new Student();

student1.setId(1);

student1.setName("李坤");

student1.setBirthDay(new Date());

Student student2 = new Student();

student2.setId(2);

student2.setName("曹贵生");

student2.setBirthDay(new Date());

Student student3 = new Student();

student3.setId(3);

student3.setName("柳波");

student3.setBirthDay(new Date());

List<Student> stulist = new ArrayList<Student>();

stulist.add(student1);

stulist.add(student2);

stulist.add(student3);

Teacher teacher1 = new Teacher();

teacher1.setId(1);

teacher1.setName("米老师");

teacher1.setTitle("教授");

Teacher teacher2 = new Teacher();

teacher2.setId(2);

teacher2.setName("丁老师");

teacher2.setTitle("讲师");

List<Teacher> teacherList = new ArrayList<Teacher>();

teacherList.add(teacher1);

teacherList.add(teacher2);

TableData td1 = new TableData();

td1.setTableName("students");

td1.setTableData(stulist);

TableData td2 = new TableData();

td2.setTableName("teachers");

td2.setTableData(teacherList);

List<TableData> tdList = new ArrayList<TableData>();

tdList.add(td1);

tdList.add(td2);

Gson gson = new Gson();

String s = gson.toJson(tdList);

System.out.println(s);

// 结果:[{"tableName":"students","tableData":[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 10:44:16 AM"},{"id":2,"name":"曹贵生","birthDay":"Jun 22, 2012 10:44:16 AM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 10:44:16 AM"}]},{"tableName":"teachers","tableData":[{"id":1,"name":"米老师","title":"教授"},{"id":2,"name":"丁老师","title":"讲师"}]}]

// 对象转为Json-->end

// /////////////////////////////////////////////////////////////////////

// 将json转为数据-->start

List<TableData> tableDatas2 = gson.fromJson(s,

new TypeToken<List<TableData>>() {

}.getType());

for (int i = 0; i < tableDatas2.size(); i++) {

TableData entityData = tableDatas2.get(i);

String tableName = entityData.getTableName();

List tableData = entityData.getTableData();

String s2 = gson.toJson(tableData);

// System.out.println(s2);

// System.out.println(entityData.getData());

if (tableName.equals("students")) {

System.out.println("students");

List<Student> retStuList = gson.fromJson(s2,

new TypeToken<List<Student>>() {

}.getType());

for (int j = 0; j < retStuList.size(); j++) {

System.out.println(retStuList.get(j));

}

} else if (tableName.equals("teachers")) {

System.out.println("teachers");

List<Teacher> retTchrList = gson.fromJson(s2,

new TypeToken<List<Teacher>>() {

}.getType());

for (int j = 0; j < retTchrList.size(); j++) {

System.out.println(retTchrList.get(j));

}

}

}

// Json转为对象-->end

}

}

输出结果:

[plain] view
plaincopy

[{"tableName":"students","tableData":[{"id":1,"name":"李坤","birthDay":"Jun 22, 2012 10:04:12 PM"},{"id":2,"name":"曹贵生","birthDay":"Jun 22, 2012 10:04:12 PM"},{"id":3,"name":"柳波","birthDay":"Jun 22, 2012 10:04:12 PM"}]},{"tableName":"teachers","tableData":[{"id":1,"name":"米老师","title":"教授"},{"id":2,"name":"丁老师","title":"讲师"}]}]

students

Student [birthDay=Fri Jun 22 22:04:12 CST 2012, id=1, name=李坤]

Student [birthDay=Fri Jun 22 22:04:12 CST 2012, id=2, name=曹贵生]

Student [birthDay=Fri Jun 22 22:04:12 CST 2012, id=3, name=柳波]

teachers

Teacher [id=1, name=米老师, title=教授]

Teacher [id=2, name=丁老师, title=讲师]