json <--->List集合,实体类 之间的相互转换

json所依赖的jar包
http://files.cnblogs.com/files/wenjie123/json_jar%E5%8C%85.rar

package com.hp.svse; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Locale; import net.sf.json.JsonConfig; import net.sf.json.processors.JsonValueProcessor; /** * Timestamp 处理器 */ public class JsonDateValueProcessor implements JsonValueProcessor { private String formatDateTime ="yyyy-MM-dd HH:mm:ss"; private String formatDate ="yyyy-MM-dd"; public Object processArrayValue(Object value, JsonConfig config) { return process(value); } public Object processObjectValue(String key, Object value, JsonConfig config) { return process(value); } private Object process(Object value){ if(value instanceof Date){ SimpleDateFormat sdf ; if(value.toString().length()<=11||value.toString().indexOf("00:00:00.0")>=0){ sdf= new SimpleDateFormat(formatDate,Locale.UK); }else{ sdf= new SimpleDateFormat(formatDateTime,Locale.UK); } return sdf.format(value); } return value == null ? "" : value.toString(); } }
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package com.hp.svse;



import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import net.sf.json.JSONArray;

import net.sf.json.JSONObject;

import net.sf.json.JsonConfig;



public class JsonTest {

    public static void main(String[] args) {

        

        /**

         * 将对象集合转换成JSON格式的字符串

         */

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

        students.add(new Student("小明1", "男", "湖北", "SVSE"));

        students.add(new Student("小明2", "女", "广东", "GIS"));

        students.add(new Student("小明3", "男", "香港", "3G"));

        JsonTest jsonTest = new JsonTest();

        String json = jsonTest.beanListToJSON(students);

        System.out.println(json);

        /**

         * 输出结果:

         * [

         *     {"sex":"男","address":"湖北","stuname":"小明1","classname":"SVSE","smallStudents":[]},

         *     {"sex":"女","address":"广东","stuname":"小明2","classname":"GIS","smallStudents":[]},

         *     {"sex":"男","address":"香港","stuname":"小明3","classname":"3G","smallStudents":[]}

         * ]

         */

        

        

        

        

        

        /**

         * 将json字符串转换成json对象  再讲json对象转换成实体对象bean

         */

        String bookCotentjsonStr = "{\"sex\":\"男\",\"address\":\"湖北\",\"stuname\":\"小明1\",\"classname\":\"SVSE\"}";

        JSONObject bookCotentjson = JSONObject.fromObject(bookCotentjsonStr);

        Student student = (Student) JSONObject.toBean(bookCotentjson, Student.class);

        System.out.println(student);

        /**

         * 输出结果:Student [address=湖北, classname=SVSE, sex=男, stuname=小明1]

         */

        

        

        

        

        /**

         * 将对象转换成JSON格式的字符串 适用于单个对象(单个对象里可以包含List<T>)的转换

         */

        List<SmallStudent> smallStudents = new ArrayList<SmallStudent>();

        for (int i = 0; i < 3; i++) {

            SmallStudent smallStudent = new SmallStudent();

            smallStudent.setName("小学生"+i);

            smallStudent.setAge("1"+i);

            smallStudents.add(smallStudent);

        }

        Student student2 = new Student("小明", "男", "武汉", "svse",smallStudents);

        String jsonStr = jsonTest.beanToJSON(student2);

        System.out.println(jsonStr);

        /**

         * 输出结果:

         * {"sex":"男","address":"武汉","stuname":"小明","classname":"svse","smallStudents":[{"sex":"","age":"10","name":"小学生0"},{"sex":"","age":"11","name":"小学生1"},{"sex":"","age":"12","name":"小学生2"}]}

         */

        

        

        

    }

    /**

     * 将集合转换成JSON格式的字符串

     */

    public <T> String beanListToJSON(List<T> t) {

        String json = "";

        JsonConfig jsonConfig = new JsonConfig();

        jsonConfig.registerJsonValueProcessor(Date.class,

                new JsonDateValueProcessor());

        if(t!=null){

        json = JSONArray.fromObject(t, jsonConfig).toString();

        }else{

            json="[]";

        }

        return json;

    }

    

    /**

     * 将对象转换成JSON格式的字符串 适用于单个对象(单个对象里可以包含List<T>)的转换

     */

    public <T> String beanToJSON(T t) {

        String json = "";

        JsonConfig jsonConfig = new JsonConfig();

        jsonConfig.registerJsonValueProcessor(Date.class,

                new JsonDateValueProcessor());

        if(t!=null){

        json = JSONObject.fromObject(t, jsonConfig).toString();

        }else{

            json="[]";

        }

        return json;

    }

}
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package com.hp.svse;



import java.util.List;



public class Student {

    private String stuname;

    private String sex;

    private String address;

    private String classname;

    private List<SmallStudent> smallStudents;

    

    public Student(String stuname, String sex, String address, String classname,List<SmallStudent> smallStudents) {

        super();

        this.stuname = stuname;

        this.sex = sex;

        this.address = address;

        this.classname = classname;

        this.smallStudents = smallStudents;

    }

    public Student(String stuname, String sex, String address, String classname) {

        super();

        this.stuname = stuname;

        this.sex = sex;

        this.address = address;

        this.classname = classname;

    }

    public Student() {

        super();

    }



    public String getStuname() {

        return stuname;

    }

    public void setStuname(String stuname) {

        this.stuname = stuname;

    }

    public String getSex() {

        return sex;

    }

    public void setSex(String sex) {

        this.sex = sex;

    }

    public String getAddress() {

        return address;

    }

    public void setAddress(String address) {

        this.address = address;

    }

    public String getClassname() {

        return classname;

    }

    public void setClassname(String classname) {

        this.classname = classname;

    }



    public List<SmallStudent> getSmallStudents() {

        return smallStudents;

    }



    public void setSmallStudents(List<SmallStudent> smallStudents) {

        this.smallStudents = smallStudents;

    }



    @Override

    public String toString() {

        return "Student [address=" + address + ", classname=" + classname

                + ", sex=" + sex + ", stuname=" + stuname + "]";

    }

    

}
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package com.hp.svse;



public class SmallStudent {

    private String name;

    private String age;

    private String sex;

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public String getAge() {

        return age;

    }

    public void setAge(String age) {

        this.age = age;

    }

    public String getSex() {

        return sex;

    }

    public void setSex(String sex) {

        this.sex = sex;

    }

    @Override

    public String toString() {

        return "SmallStudent [age=" + age + ", name=" + name + ", sex=" + sex

                + "]";

    }

}

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