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:

 

 

 

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 + "]";
    }

}

 

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:

 

 

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)

 

 

 

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:

 

[{"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]