原文http://my.oschina.net/leejun2005/blog/268634 在日志解析，前后端数据传输交互中，经常会遇到 String 与 map、json、xml 等格式相互转换与解析的场景，其中 json 基本成为了跨语言、跨前后端的事实上的标准数据交互格式。应该来说各个语言中 解析 json 的库都一大片（具体 json 格式与三方库的介绍请见： http://www.json.org/json-zh.html ），比如 python 都集成在了内置库中，成为标准 API，今天我们要聊的是 java 中如何方便的使用 json 格式。
public static final Object parse(String text);
// 把JSON文本parse为JSONObject或者JSONArray
public static final JSONObject parseObject(String text)； // 把JSON文本parse成JSONObject
public static final T parseObject(String text, Class clazz);
// 把JSON文本parse为JavaBean
public static final JSONArray parseArray(String text);
// 把JSON文本parse成JSONArray
public static final List parseArray(String text, Class clazz);
//把JSON文本parse成JavaBean集合
public static final String toJSONString(Object object);
// 将JavaBean序列化为JSON文本
public static final String toJSONString(Object object, boolean prettyFormat);
// 将JavaBean序列化为带格式的JSON文本
public static final Object toJSON(Object javaObject);
将JavaBean转换为JSONObject或者JSONArray。
3、有关类库的一些说明
SerializeWriter：相当于StringBuffer
JSONArray：相当于List
package lavasoft.stu.json;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializeConfig;
import com.alibaba.fastjson.serializer.SimpleDateFormatSerializer;
import java.util.*;
/**
* Created by IntelliJ IDEA.
*
* @author leizhimin 11-11-22 上午9:15
*/
public class Foo {
private String vString = "vStringhehhehe";
private char vchar = 'x';
private byte vbyte = 64;
private short vshort = 128;
private int vint = 65535;
private long vlong = 9999999L;
private float vfloat = 12.1f;
private double vdouble = 22.203d;
private boolean vboolean = false;
// private Date vdate = new Date();
private Date dddd = new Date();
private Date vDate = new Date();
private Date v_Date = new Date();
private Object vnull = null;
private String[] avString = {"aaa", "bbb", "ccc"};
private int[] avint = {1, 2, 3, 4};
private boolean[] avboolean = {true, false, true, true};
private List listString = new ArrayList();
private Map map = new HashMap();
private Bar bar = new Bar();
private Bar[] avBar = {new Bar(), new Bar()};
private List listBar = new ArrayList();
{
listString.add("listString1");
listString.add("listString2");
listString.add("listString3");
map.put("x", "s11111x");
map.put("y", "s22222y");
map.put("z", "s33333z");
listBar.add(new Bar());
listBar.add(new Bar());
listBar.add(new Bar());
} public String getvString() {
return vString;
} public void setvString(String vString) {
this.vString = vString;
} public char getVchar() {
return vchar;
} public void setVchar(char vchar) {
this.vchar = vchar;
} public byte getVbyte() {
return vbyte;
} public void setVbyte(byte vbyte) {
this.vbyte = vbyte;
} public short getVshort() {
return vshort;
} public void setVshort(short vshort) {
this.vshort = vshort;
} public int getVint() {
return vint;
} public void setVint(int vint) {
this.vint = vint;
} public long getVlong() {
return vlong;
} public void setVlong(long vlong) {
this.vlong = vlong;
} public float getVfloat() {
return vfloat;
} public void setVfloat(float vfloat) {
this.vfloat = vfloat;
} public double getVdouble() {
return vdouble;
} public void setVdouble(double vdouble) {
this.vdouble = vdouble;
} public boolean isVboolean() {
return vboolean;
} public void setVboolean(boolean vboolean) {
this.vboolean = vboolean;
} public Date getDddd() {
return dddd;
} public void setDddd(Date dddd) {
this.dddd = dddd;
} public Date getV_Date() {
return v_Date;
} public void setV_Date(Date v_Date) {
this.v_Date = v_Date;
} public Date getvDate() {
return vDate;
} public void setvDate(Date vDate) {
this.vDate = vDate;
} public Object getVnull() {
return vnull;
} public void setVnull(Object vnull) {
this.vnull = vnull;
} public String[] getAvString() {
return avString;
} public void setAvString(String[] avString) {
this.avString = avString;
} public int[] getAvint() {
return avint;
} public void setAvint(int[] avint) {
this.avint = avint;
} public boolean[] getAvboolean() {
return avboolean;
} public void setAvboolean(boolean[] avboolean) {
this.avboolean = avboolean;
} public List getListString() {
return listString;
} public void setListString(List listString) {
this.listString = listString;
} public Map getMap() {
return map;
} public void setMap(Map map) {
this.map = map;
} public Bar getBar() {
return bar;
} public void setBar(Bar bar) {
this.bar = bar;
} public Bar[] getAvBar() {
return avBar;
} public void setAvBar(Bar[] avBar) {
this.avBar = avBar;
} public List getListBar() {
return listBar;
} public void setListBar(List listBar) {
this.listBar = listBar;
}
} package lavasoft.stu.json;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializeConfig;
import com.alibaba.fastjson.serializer.SimpleDateFormatSerializer;
import java.util.Date;
import java.util.Random;
/**
* Created by IntelliJ IDEA.
*
* @author leizhimin 11-11-22 上午9:15
*/
public class Bar {
public static SerializeConfig mapping = new SerializeConfig();
private String barName;
private int barAge;
private Date barDate = new Date();
static {
mapping.put(Date.class, new SimpleDateFormatSerializer("yyyy-MM-dd"));
}
{
Random r = new Random();
barName = "sss_"+String.valueOf(r.nextFloat());
barAge = r.nextInt();
} public static void main(String[] args) {
Object obj = JSON.toJSON(new Bar());
String x1 = JSON.toJSONString(new Bar(), true);
System.out.println(x1);
String x2 = JSON.toJSONString(new Bar(), mapping);
System.out.println(x2);
} public String getBarName() {
return barName;
} public void setBarName(String barName) {
this.barName = barName;
} public int getBarAge() {
return barAge;
} public void setBarAge(int barAge) {
this.barAge = barAge;
} public Date getBarDate() {
return barDate;
} public void setBarDate(Date barDate) {
this.barDate = barDate;
} @Override
public String toString() {
return "Bar{" +
"barName='" + barName + '\'' +
", barAge=" + barAge +
", barDate=" + barDate +
'}';
}
}package lavasoft.stu.json;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.serializer.SerializeConfig;
import com.alibaba.fastjson.serializer.SimpleDateFormatSerializer;
import java.util.*;
/**
* Created by 2IntelliJ IDEA.
*
* @author leizhimin 11-11-22 上午9:45
*/
public class Test {
private static SerializeConfig mapping = new SerializeConfig();
static {
mapping.put(Date.class, new SimpleDateFormatSerializer("yyyy-MM-dd HH:mm:ss"));
} public static void main(String[] args) {
Foo f1 = new Foo();
Date date = new Date();
String text = JSON.toJSONString(date, mapping);
System.out.println(text);
System.out.println(JSON.toJSONString(f1, true));
String x2 =JSON.toJSONString(f1, mapping);
System.out.println(x2);
} public static void json2List(){
//List -> JSON array
List barList = new ArrayList();
barList.add(new Bar());
barList.add(new Bar());
barList.add(new Bar());
String json= JSON.toJSONString(barList, true);
System.out.println(json);
//JSON array -> List
List barList1 = JSON.parseArray(json,Bar.class);
for (Bar bar : barList1) {
System.out.println(bar.toString());
}
} public static void json2Map(){
//Map -> JSON
Map map = new HashMap();
map.put("a",new Bar());
map.put("b",new Bar());
map.put("c",new Bar());
String json = JSON.toJSONString(map,true);
System.out.println(json);
//JSON -> Map
Map map1 = (Map)JSON.parse(json);
for (String key : map1.keySet()) {
System.out.println(key+":"+map1.get(key));
}
} public static void array2JSON(){
String[] arr_String= {"a","b","c"};
String json_arr_String = JSON.toJSONString(arr_String,true);
System.out.println(json_arr_String);
JSONArray jsonArray = JSON.parseArray(json_arr_String);
for (Object o : jsonArray) {
System.out.println(o);
}
System.out.println(jsonArray);
}
public static void array2JSON2(){
Bar[] arr_Bar= {new Bar(),new Bar(),new Bar()};
String json_arr_Bar = JSON.toJSONString(arr_Bar,true);
System.out.println(json_arr_Bar);
JSONArray jsonArray = JSON.parseArray(json_arr_Bar);
for (Object o : jsonArray) {
System.out.println(o);
}
System.out.println(jsonArray);
} public static void map2JSON(){
Map map = new HashMap();
map.put("a","aaa");
map.put("b","bbb");
map.put("c","ccc");
String json=JSON.toJSONString(map);
System.out.println(json);
Map map1 = JSON.parseObject(json);
for (Object o : map.entrySet()) {
Map.Entry entry = (Map.Entry)o;
System.out.println(entry.getKey()+"--->"+entry.getValue());
}
}
} "2011-11-23 23:30:33"
{
"avBar":[{
"barAge":174398800,
"barDate":1322062233062,
"barName":"sss_0.62378174"
},{
"barAge":38938962,
"barDate":1322062233062,
"barName":"sss_0.36014742"
}],
"avString":["aaa","bbb","ccc"],
"avboolean":[true,false,true,true],
"avint":[1,2,3,4],
"bar":{
"barAge":1601495948,
"barDate":1322062233062,
"barName":"sss_0.46644872"
},
"dddd":1322062233046,
"listBar":[
{
"barAge":-1090113522,
"barDate":1322062233062,
"barName":"sss_0.83562374"
},
{
"barAge":478603194,
"barDate":1322062233062,
"barName":"sss_0.59483266"
},
{
"barAge":1118357669,
"barDate":1322062233062,
"barName":"sss_0.9961642"
}
],
"listString":[
"listString1",
"listString2",
"listString3"
],
"map":{"x":"s11111x","y":"s22222y","z":"s33333z"},
"v_Date":1322062233046,
"vboolean":false,
"vbyte":64,
"vchar":"x",
"vdouble":22.203,
"vfloat":12.1,
"vint":65535,
"vlong":9999999,
"vshort":128
}
{"avBar":[{"barAge":174398800,"barDate":"2011-11-23 23:30:33","barName":"sss_0.62378174"},{"barAge":38938962,"barDate":"2011-11-23 23:30:33","barName":"sss_0.36014742"}],"avString":["aaa","bbb","ccc"],"avboolean":[true,false,true,true],"avint":[1,2,3,4],"bar":{"barAge":1601495948,"barDate":"2011-11-23 23:30:33","barName":"sss_0.46644872"},"dddd":"2011-11-23 23:30:33","listBar":[{"barAge":-1090113522,"barDate":"2011-11-23 23:30:33","barName":"sss_0.83562374"},{"barAge":478603194,"barDate":"2011-11-23 23:30:33","barName":"sss_0.59483266"},{"barAge":1118357669,"barDate":"2011-11-23 23:30:33","barName":"sss_0.9961642"}],"listString":["listString1","listString2","listString3"],"map":{"x":"s11111x","y":"s22222y","z":"s33333z"},"v_Date":"2011-11-23 23:30:33","vboolean":false,"vbyte":64,"vchar":"x","vdouble":22.203,"vfloat":12.1,"vint":65535,"vlong":9999999,"vshort":128} Process finished with exit code 0JSONObject json = new JSONObject();
json.put("aa", "11");
json.put("bb", "22");
json.put("cc", "33");
String jsonStr = json.toString();
System.out.println(jsonStr);
// {"aa":"11","bb":"22","cc":"33"} System.out.println(JSONObject.parseObject(jsonStr).get("aa"));
// 11String o = "{'area':{'area':'1','pagetype':'home'},'pagetype':'home'}";
System.out.println(((Map) JSONObject.parseObject(o).get("area")).get("area"));
// 1
String text = JSON.toJSONString(o);
Map userMap =
JSON.parseObject(o, new TypeReference() {});
System.out.println(((Map) userMap.get("area")).get("NotExsit"));
// nullSystem.out.println(JSON.toJSONString((Map) userMap.get("area")));
// {"area":"1","pagetype":"home"} 【Web开发|FastJSON 简介及其Map/JSON/String 互转】 http://blog.csdn.net/glarystar/article/details/6654494推荐阅读
