json、javaBean、xml互转的几种工具介绍

 Json、javaBean、xml互转的几种工具介绍

　　工作中经常要用到Json、JavaBean、Xml之间的相互转换，用到了很多种方式，这里做下总结，以供参考。

　　现在主流的转换工具有json-lib、jackson、fastjson等，我为大家一一做简单介绍，主要还是以代码形式贴出如何简单应用这些工具的，更多高级功能还需大家深入研究。

首先是json-lib，算是很早的转换工具了，用的人很多，说实在现在完全不适合了，缺点比较多，依赖的第三方实在是比较多，效率低下，API也比较繁琐，说他纯粹是因为以前的老项目很多人都用到它。不废话，开始上代码。

需要的maven依赖：

<dependency>  
        <groupId>net.sf.json-lib</groupId>  
        <artifactId>json-lib</artifactId>  
        <version>2.4</version>  
        <classifier>jdk15</classifier>  
    </dependency>
    <dependency>
        <groupId>xom</groupId>
        <artifactId>xom</artifactId>
        <version>1.1</version>
    </dependency> 
    <dependency>
        <groupId>xalan</groupId>
        <artifactId>xalan</artifactId>
        <version>2.7.1</version>
    </dependency>

使用json-lib实现多种转换

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.swing.text.Document;
import net.sf.ezmorph.Morpher;
import net.sf.ezmorph.MorpherRegistry;
import net.sf.ezmorph.bean.BeanMorpher;
import net.sf.ezmorph.object.DateMorpher;
import net.sf.json.JSON;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import net.sf.json.JsonConfig;
import net.sf.json.processors.JsonValueProcessor;
import net.sf.json.util.CycleDetectionStrategy;
import net.sf.json.util.JSONUtils;
import net.sf.json.xml.XMLSerializer;

/**
 * json-lib utils
 * @author magic_yy
 * @see json-lib.sourceforge.net/
 * @see https://github.com/aalmiray/Json-lib
 *
 */
public class JsonLibUtils {
    
    public static JsonConfig config = new JsonConfig();
    
    static{
        config.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);//忽略循环，避免死循环
        config.registerJsonValueProcessor(Date.class, new JsonValueProcessor() {//处理Date日期转换
            @Override
            public Object processObjectValue(String arg0, Object arg1, JsonConfig arg2) {
                 SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                    Date d=(Date) arg1;
                    return sdf.format(d);
            }
            @Override
            public Object processArrayValue(Object arg0, JsonConfig arg1) {
                return null;
            }
        });
    }
    
    /** 
     * java object convert to json string
     */  
    public static String pojo2json(Object obj){
        return JSONObject.fromObject(obj,config).toString();//可以用toString(1)来实现格式化，便于阅读  
    }  
      
    /** 
     * array、map、Javabean convert to json string
     */  
    public static String object2json(Object obj){  
        return JSONSerializer.toJSON(obj).toString();  
    }  
      
    /** 
     * xml string convert to json string
     */  
    public static String xml2json(String xmlString){  
        XMLSerializer xmlSerializer = new XMLSerializer();  
        JSON json = xmlSerializer.read(xmlString);  
        return json.toString();  
    }  
      
    /** 
     * xml document convert to json string
     */  
    public static String xml2json(Document xmlDocument){  
        return xml2json(xmlDocument.toString());  
    }  
      
    /** 
     * json string convert to javaBean
     * @param <T>
     */  
    @SuppressWarnings("unchecked")
    public static <T> T json2pojo(String jsonStr,Class<T> clazz){  
        JSONObject jsonObj = JSONObject.fromObject(jsonStr);  
        T obj = (T) JSONObject.toBean(jsonObj, clazz);  
        return obj;  
    }
    
    /**
     * json string convert to map
     */
    public static Map<String,Object> json2map(String jsonStr){
        JSONObject jsonObj = JSONObject.fromObject(jsonStr);
        Map<String,Object> result = (Map<String, Object>) JSONObject.toBean(jsonObj, Map.class);
        return result;
    }
    
    /**
     * json string convert to map with javaBean
     */
    public static <T> Map<String,T> json2map(String jsonStr,Class<T> clazz){
        JSONObject jsonObj = JSONObject.fromObject(jsonStr);
        Map<String,T> map = new HashMap<String, T>();
        Map<String,T> result = (Map<String, T>) JSONObject.toBean(jsonObj, Map.class, map);
        MorpherRegistry morpherRegistry = JSONUtils.getMorpherRegistry();
        Morpher dynaMorpher = new BeanMorpher(clazz,morpherRegistry);
        morpherRegistry.registerMorpher(dynaMorpher);
        morpherRegistry.registerMorpher(new DateMorpher(new String[]{ "yyyy-MM-dd HH:mm:ss" }));
        for (Entry<String,T> entry : result.entrySet()) {
            map.put(entry.getKey(), (T)morpherRegistry.morph(clazz, entry.getValue()));
        }
        return map;
    }
      
    /** 
     * json string convert to array
     */  
    public static Object[] json2arrays(String jsonString) {  
        JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON(jsonString);
//        JSONArray jsonArray = JSONArray.fromObject(jsonString);  
        JsonConfig jsonConfig = new JsonConfig();
        jsonConfig.setArrayMode(JsonConfig.MODE_OBJECT_ARRAY);
        Object[] objArray = (Object[]) JSONSerializer.toJava(jsonArray,jsonConfig);
        return objArray;
    }  
      
    /** 
     * json string convert to list
     * @param <T>
     */  
    @SuppressWarnings({ "unchecked", "deprecation" })
    public static <T> List<T> json2list(String jsonString, Class<T> pojoClass){  
        JSONArray jsonArray = JSONArray.fromObject(jsonString);  
        return JSONArray.toList(jsonArray, pojoClass);
    }  
      
    /** 
     * object convert to xml string
     */  
    public static String obj2xml(Object obj){  
        XMLSerializer xmlSerializer = new XMLSerializer();  
        return xmlSerializer.write(JSONSerializer.toJSON(obj));  
    }  
      
    /** 
     * json string convert to xml string
     */  
    public static String json2xml(String jsonString){  
        XMLSerializer xmlSerializer = new XMLSerializer();  
        xmlSerializer.setTypeHintsEnabled(true);//是否保留元素类型标识，默认true
        xmlSerializer.setElementName("e");//设置元素标签，默认e
        xmlSerializer.setArrayName("a");//设置数组标签，默认a
        xmlSerializer.setObjectName("o");//设置对象标签，默认o
        return xmlSerializer.write(JSONSerializer.toJSON(jsonString));  
    }
    
}

测试代码如下：

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import net.sf.ezmorph.test.ArrayAssertions;
import org.junit.Assert;
import org.junit.Test;

public class JsonLibUtilsTest {

    @Test
    public void pojo2json_test(){
        User user = new User(1, "张三");
        String json = JsonLibUtils.pojo2json(user);
        Assert.assertEquals("{"id":1,"name":"张三"}", json);
    }
    
    @Test
    public void object2json_test(){
        int[] intArray = new int[]{1,4,5};
        String json = JsonLibUtils.object2json(intArray);
        Assert.assertEquals("[1,4,5]", json);
        User user1 = new User(1,"张三");
        User user2 = new User(2,"李四");
        User[] userArray = new User[]{user1,user2};
        String json2 = JsonLibUtils.object2json(userArray);
        Assert.assertEquals("[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]", json2);
        List<User> userList = new ArrayList<>();
        userList.add(user1);
        userList.add(user2);
        String json3 = JsonLibUtils.object2json(userList);
        Assert.assertEquals("[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]", json3);
        //这里的map的key必须为String类型
        Map<String,Object> map = new HashMap<>();
        map.put("id", 1);
        map.put("name", "张三");
        String json4 = JsonLibUtils.object2json(map);
        Assert.assertEquals("{"id":1,"name":"张三"}", json4);
        Map<String,User> map2 = new HashMap<>();
        map2.put("user1", user1);
        map2.put("user2", user2);
        String json5 = JsonLibUtils.object2json(map2);
        Assert.assertEquals("{"user2":{"id":2,"name":"李四"},"user1":{"id":1,"name":"张三"}}", json5);
    }
    
    @Test
    public void xml2json_test(){
        String xml1 = "<User><id>1</id><name>张三</name></User>";
        String json = JsonLibUtils.xml2json(xml1);
        Assert.assertEquals("{"id":"1","name":"张三"}", json);
        String xml2 = "<Response><CustID>1300000428</CustID><Items><Item><Sku_ProductNo>sku_0004</Sku_ProductNo></Item><Item><Sku_ProductNo>0005</Sku_ProductNo></Item></Items></Response>";
        String json2 = JsonLibUtils.xml2json(xml2);
        //处理数组时expected是处理结果，但不是我们想要的格式
        String expected = "{"CustID":"1300000428","Items":[{"Sku_ProductNo":"sku_0004"},{"Sku_ProductNo":"0005"}]}";
        Assert.assertEquals(expected, json2);
        //实际上我们想要的是expected2这种格式,所以用json-lib来实现含有数组的xml to json是不行的
        String expected2 = "{"CustID":"1300000428","Items":{"Item":[{"Sku_ProductNo":"sku_0004"},{"Sku_ProductNo":"0005"}]}}";
        Assert.assertEquals(expected2, json2);
    }
    
    @Test
    public void json2arrays_test(){
        String json = "["张三","李四"]";
        Object[] array = JsonLibUtils.json2arrays(json);
        Object[] expected = new Object[] { "张三", "李四" };
        ArrayAssertions.assertEquals(expected, array);                                                                                            
        //无法将JSON字符串转换为对象数组
        String json2 = "[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]";
        Object[] array2 = JsonLibUtils.json2arrays(json2);
        User user1 = new User(1,"张三");
        User user2 = new User(2,"李四");
        Object[] expected2 = new Object[] { user1, user2 };
        ArrayAssertions.assertEquals(expected2, array2);
    }
    
    @Test
    public void json2list_test(){
        String json = "["张三","李四"]";
        List<String> list = JsonLibUtils.json2list(json, String.class);
        Assert.assertTrue(list.size()==2&&list.get(0).equals("张三")&&list.get(1).equals("李四"));
        String json2 = "[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]";
        List<User> list2 = JsonLibUtils.json2list(json2, User.class);
        Assert.assertTrue(list2.size()==2&&list2.get(0).getId()==1&&list2.get(1).getId()==2);
    }
    
    @Test
    public void json2pojo_test(){
        String json = "{"id":1,"name":"张三"}";
        User user = (User) JsonLibUtils.json2pojo(json, User.class);
        Assert.assertEquals(json, user.toString());
    }
    
    @Test
    public void json2map_test(){
        String json = "{"id":1,"name":"张三"}";
        Map map = JsonLibUtils.json2map(json);
        int id = Integer.parseInt(map.get("id").toString());
        String name = map.get("name").toString();
        System.out.println(name);
        Assert.assertTrue(id==1&&name.equals("张三"));
        String json2 = "{"user2":{"id":2,"name":"李四"},"user1":{"id":1,"name":"张三"}}";
        Map map2 = JsonLibUtils.json2map(json2, User.class);
        System.out.println(map2);
    }
    
    @Test
    public void json2xml_test(){
        String json = "{"id":1,"name":"张三"}";
        String xml = JsonLibUtils.json2xml(json);
        Assert.assertEquals("<?xml version="1.0" encoding="UTF-8"?>
<o><id type="number">1</id><name type="string">张三</name></o>
", xml);
        System.out.println(xml);
        String json2 = "[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]";
        String xml2 = JsonLibUtils.json2xml(json2);
        System.out.println(xml2);
        Assert.assertEquals("<?xml version="1.0" encoding="UTF-8"?>
<a><e class="object"><id type="number">1</id><name type="string">张三</name></e><e class="object"><id type="number">2</id><name type="string">李四</name></e></a>
", xml2);
    }
    
    public static class User{
        private int id;
        private String name;
        
        public User() {
        }
        public User(int id, String name) {
            this.id = id;
            this.name = name;
        }
        @Override
        public String toString() {
            return "{"id":"+id+","name":""+name+""}";
        }
        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;
        }
    }
}

json-lib在XML转换为JSON在有数组的情况下会有问题，还有在JSON转换为XML时都会有元素标识如<o><a><e>等，在一般情况下我们可能都不需要，暂时还不知道如何过滤这些元素名称。

因为json-lib的种种缺点，基本停止了更新，也不支持注解转换，后来便有了jackson流行起来，它比json-lib的转换效率要高很多，依赖很少，社区也比较活跃

我们依旧开始上代码，首先是它的依赖：

<dependency>  
    <groupId>com.fasterxml.jackson.dataformat</groupId>  
    <artifactId>jackson-dataformat-xml</artifactId>  
    <version>2.1.3</version>  
</dependency>  
<dependency>  
    <groupId>com.fasterxml.jackson.core</groupId>  
    <artifactId>jackson-databind</artifactId>  
    <version>2.1.3</version>  
    <type>java-source</type>  
    <scope>compile</scope>  
</dependency>  

这里我要说下，有很多基于jackson的工具，大家可以按照自己的实际需求来需找对应的依赖，我这里为了方便转换xml所以用了dataformat-xml和databind

 使用jackson实现多种转换：

package cn.yangyong.fodder.util;

import java.io.StringWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;


public class JacksonUtils {
    
    private static ObjectMapper objectMapper = new ObjectMapper();
    private static XmlMapper xmlMapper = new XmlMapper();
    
    /**
     * javaBean,list,array convert to json string
     */
    public static String obj2json(Object obj) throws Exception{
        return objectMapper.writeValueAsString(obj);
    }
    
    /**
     * json string convert to javaBean
     */
    public static <T> T json2pojo(String jsonStr,Class<T> clazz) throws Exception{
        return objectMapper.readValue(jsonStr, clazz);
    }
    
    /**
     * json string convert to map
     */
    public static <T> Map<String,Object> json2map(String jsonStr)throws Exception{
        return objectMapper.readValue(jsonStr, Map.class);
    }
    
    /**
     * json string convert to map with javaBean
     */
    public static <T> Map<String,T> json2map(String jsonStr,Class<T> clazz)throws Exception{
        Map<String,Map<String,Object>> map =  objectMapper.readValue(jsonStr, new TypeReference<Map<String,T>>() {
        });
        Map<String,T> result = new HashMap<String, T>();
        for (Entry<String, Map<String,Object>> entry : map.entrySet()) {
            result.put(entry.getKey(), map2pojo(entry.getValue(), clazz));
        }
        return result;
    }
    
    /**
     * json array string convert to list with javaBean
     */
    public static <T> List<T> json2list(String jsonArrayStr,Class<T> clazz)throws Exception{
        List<Map<String,Object>> list = objectMapper.readValue(jsonArrayStr, new TypeReference<List<T>>() {
        });
        List<T> result = new ArrayList<>();
        for (Map<String, Object> map : list) {
            result.add(map2pojo(map, clazz));
        }
        return result;
    }
    
    /**
     * map convert to javaBean
     */
    public static <T> T map2pojo(Map map,Class<T> clazz){
        return objectMapper.convertValue(map, clazz);
    }
    
    /**
     * json string convert to xml string
     */
    public static String json2xml(String jsonStr)throws Exception{
        JsonNode root = objectMapper.readTree(jsonStr);
        String xml = xmlMapper.writeValueAsString(root);
        return xml;
    }
    
    /**
     * xml string convert to json string
     */
    public static String xml2json(String xml)throws Exception{
        StringWriter w = new StringWriter();
        JsonParser jp = xmlMapper.getFactory().createParser(xml);
        JsonGenerator jg = objectMapper.getFactory().createGenerator(w);
        while (jp.nextToken() != null) {
            jg.copyCurrentEvent(jp);
        }
        jp.close();
        jg.close();
        return w.toString();
    }
    
}

只用了其中的一部分功能，有关annotation部分因为从没用到所以没写，大家可以自行研究下，我这里就不提了。jackson的测试代码如下：

package cn.yangyong.fodder.util;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.junit.Assert;
import org.junit.Test;
import cn.yangyong.fodder.util.JacksonUtils;

public class JacksonUtilsTest {

    @Test
    public void test_pojo2json() throws Exception{
        String json = JacksonUtils.obj2json(new User(1, "张三"));
        Assert.assertEquals("{"id":1,"name":"张三"}", json);
        List<User> list = new ArrayList<>();
        list.add(new User(1, "张三"));
        list.add(new User(2, "李四"));
        String json2 = JacksonUtils.obj2json(list);
        Assert.assertEquals("[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]", json2);
        Map<String,User> map = new HashMap<>();
        map.put("user1", new User(1, "张三"));
        map.put("user2", new User(2, "李四"));
        String json3 = JacksonUtils.obj2json(map);
        Assert.assertEquals("{"user2":{"id":2,"name":"李四"},"user1":{"id":1,"name":"张三"}}", json3);
    }
    
    @Test
    public void test_json2pojo() throws Exception{
        String json = "{"id":1,"name":"张三"}";
        User user = JacksonUtils.json2pojo(json, User.class);
        Assert.assertTrue(user.getId()==1&&user.getName().equals("张三"));
    }
    
    @Test
    public void test_json2map() throws Exception{
        String json = "{"id":1,"name":"张三"}";
        Map<String,Object> map = JacksonUtils.json2map(json);
        Assert.assertEquals("{id=1, name=张三}", map.toString());
        String json2 = "{"user2":{"id":2,"name":"李四"},"user1":{"id":1,"name":"张三"}}";
        Map<String,User> map2 = JacksonUtils.json2map(json2, User.class);
        User user1 = map2.get("user1");
        User user2 = map2.get("user2");
        Assert.assertTrue(user1.getId()==1&&user1.getName().equals("张三"));
        Assert.assertTrue(user2.getId()==2&&user2.getName().equals("李四"));
    }
    
    @Test
    public void test_json2list() throws Exception{
        String json = "[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]";
        List<User> list = JacksonUtils.json2list(json,User.class);
        User user1 = list.get(0);
        User user2 = list.get(1);
        Assert.assertTrue(user1.getId()==1&&user1.getName().equals("张三"));
        Assert.assertTrue(user2.getId()==2&&user2.getName().equals("李四"));
    }
    
    @Test
    public void test_map2pojo(){
        Map<String,Object> map = new HashMap<String, Object>();
        map.put("id", 1);
        map.put("name", "张三");
        User user = JacksonUtils.map2pojo(map, User.class);
        Assert.assertTrue(user.getId()==1&&user.getName().equals("张三"));
        System.out.println(user);
    }
    
    @Test
    public void test_json2xml() throws Exception{
        String json = "{"id":1,"name":"张三"}";
        String xml = JacksonUtils.json2xml(json);
        Assert.assertEquals("<ObjectNode xmlns=""><id>1</id><name>张三</name></ObjectNode>", xml);
        String json2 = "{"Items":{"RequestInterfaceSku":[{"Sku_ProductNo":"sku_0004"},{"Sku_ProductNo":"sku_0005"}]}}";
        String xml2 = JacksonUtils.json2xml(json2);
        Assert.assertEquals("<ObjectNode xmlns=""><Items><RequestInterfaceSku><Sku_ProductNo>sku_0004</Sku_ProductNo></RequestInterfaceSku><RequestInterfaceSku><Sku_ProductNo>sku_0005</Sku_ProductNo></RequestInterfaceSku></Items></ObjectNode>", xml2);
    }
    
    @Test
    public void test_xml2json() throws Exception{
        String xml = "<ObjectNode xmlns=""><id>1</id><name>张三</name></ObjectNode>";
        String json = JacksonUtils.xml2json(xml);
        Assert.assertEquals("{"id":1,"name":"张三"}", json);
        String xml2 = "<ObjectNode xmlns=""><Items><RequestInterfaceSku><Sku_ProductNo>sku_0004</Sku_ProductNo></RequestInterfaceSku><RequestInterfaceSku><Sku_ProductNo>sku_0005</Sku_ProductNo></RequestInterfaceSku></Items></ObjectNode>";
        String json2 = JacksonUtils.xml2json(xml2);
        //expected2是我们想要的格式，但实际结果确实expected1，所以用jackson实现xml直接转换为json在遇到数组时是不可行的
        String expected1 = "{"Items":{"RequestInterfaceSku":{"Sku_ProductNo":"sku_0004"},"RequestInterfaceSku":{"Sku_ProductNo":"sku_0005"}}}";
        String expected2 = "{"Items":{"RequestInterfaceSku":[{"Sku_ProductNo":"sku_0004"},{"Sku_ProductNo":"sku_0005"}]}}";
        Assert.assertEquals(expected1, json2);
        Assert.assertEquals(expected2, json2);
    }
    
    private static class User{
        private int id;
        private String name; 
        
        public User() {
        }
        public User(int id, String name) {
            this.id = id;
            this.name = name;
        }
        @Override
        public String toString() {
            return "{"id":"+id+","name":""+name+""}";
        }
        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;
        }
    }
}

测试后发现xml转换为json时也有问题，居然不认识数组，真是悲剧。好吧就由它吧，也可能是我的方法不正确。

jackson一直很主流，社区和文档支持也很充足，但有人还是嫌它不够快，不够简洁，于是便有了fastjson，看名字就知道它的主要特点就是快，可能在功能和其他支持方面不能和jackson媲美，但天下武功，唯快不破，这就决定了fastjson有了一定的市场。不解释，直接上代码。

<dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>1.1.33</version>
    </dependency>

沃，除了自身零依赖，再看它的API使用。
使用fastjson实现多种转换：

package cn.yangyong.fodder.util;

import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.TypeReference;
import com.alibaba.fastjson.serializer.SerializeConfig;
import com.alibaba.fastjson.serializer.SimpleDateFormatSerializer;

/**
 * fastjson utils
 */
public class FastJsonUtils {
    
    private static SerializeConfig mapping = new SerializeConfig();
    
    static{
        mapping.put(Date.class, new SimpleDateFormatSerializer("yyyy-MM-dd HH:mm:ss"));
    }
    
    /**
     * javaBean、list、map convert to json string
     */
    public static String obj2json(Object obj){
//        return JSON.toJSONString(obj,SerializerFeature.UseSingleQuotes);//使用单引号
//        return JSON.toJSONString(obj,true);//格式化数据，方便阅读
        return JSON.toJSONString(obj,mapping);
    }
    
    /**
     * json string convert to javaBean、map
     */
    public static <T> T json2obj(String jsonStr,Class<T> clazz){
        return JSON.parseObject(jsonStr,clazz);
    }
    
    /**
     * json array string convert to list with javaBean
     */
    public static <T> List<T> json2list(String jsonArrayStr,Class<T> clazz){
        return JSON.parseArray(jsonArrayStr, clazz);
    }
    
    /**
     * json string convert to map
     */
    public static <T> Map<String,Object> json2map(String jsonStr){
        return json2obj(jsonStr, Map.class);
    }
    
    /**
     * json string convert to map with javaBean
     */
    public static <T> Map<String,T> json2map(String jsonStr,Class<T> clazz){
        Map<String,T> map = JSON.parseObject(jsonStr, new TypeReference<Map<String, T>>() {});
        for (Entry<String, T> entry : map.entrySet()) {
            JSONObject obj = (JSONObject) entry.getValue();
            map.put(entry.getKey(), JSONObject.toJavaObject(obj, clazz));
        }
        return map;
    }
}

API真的很简洁，很方便，这里依旧只用了部分功能，关于注解部分请大家自行研究。测试代码如下：

package cn.yangyong.fodder.util;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.junit.Assert;
import org.junit.Test;

public class FastJsonTest {
    
    @Test
    public void test_dateFormat(){
        Date date = new Date();
        String json = FastJsonUtils.obj2json(date);
        String expected = """+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date)+""";
        Assert.assertEquals(expected, json);
    }
    
    @Test
    public void test_obj2json(){
        User user = new User(1, "张三");
        String json = FastJsonUtils.obj2json(user);
        Assert.assertEquals("{"id":1,"name":"张三"}", json);
        List<User> list = new ArrayList<>();
        list.add(new User(1, "张三"));
        list.add(new User(2, "李四"));
        String json2 = FastJsonUtils.obj2json(list);
        Assert.assertEquals("[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]", json2);
        Map<String,User> map = new HashMap<>();
        map.put("user1", new User(1, "张三"));
        map.put("user2", new User(2, "李四"));
        String json3 = FastJsonUtils.obj2json(map);
        Assert.assertEquals("{"user1":{"id":1,"name":"张三"},"user2":{"id":2,"name":"李四"}}", json3);
    }
    
    @Test
    public void test_json2obj(){
        String json = "{"id":1,"name":"张三"}";
        User user = FastJsonUtils.json2obj(json, User.class);
        Assert.assertTrue(user.getId()==1&&user.getName().equals("张三"));
    }
    
    @Test
    public void test_json2list(){
        String json = "[{"id":1,"name":"张三"},{"id":2,"name":"李四"}]";
        List<User> list = FastJsonUtils.json2list(json, User.class);
        User user1 = list.get(0);
        User user2 = list.get(1);
        Assert.assertTrue(user1.getId()==1&&user1.getName().equals("张三"));
        Assert.assertTrue(user2.getId()==2&&user2.getName().equals("李四"));
    }
    
    @Test
    public void test_json2map() throws Exception{
        String json = "{"id":1,"name":"张三"}";
        Map<String,Object> map = FastJsonUtils.json2map(json);
        Assert.assertEquals("{id=1, name=张三}", map.toString());
        String json2 = "{"user2":{"id":2,"name":"李四"},"user1":{"id":1,"name":"张三"}}";
        Map<String,User> map2 = FastJsonUtils.json2map(json2, User.class);
        User user1 = map2.get("user1");
        User user2 = map2.get("user2");
        Assert.assertTrue(user1.getId()==1&&user1.getName().equals("张三"));
        Assert.assertTrue(user2.getId()==2&&user2.getName().equals("李四"));
    }
    
    private static class User{
        private int id;
        private String name; 
        
        public User() {
        }
        public User(int id, String name) {
            this.id = id;
            this.name = name;
        }
        @Override
        public String toString() {
            return "{"id":"+id+","name":""+name+""}";
        }
        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;
        }
    }
    
}

只有json和javaBean直接的相互转换，没有xml的转换，真可惜。好吧，谁叫人家定位不一样呢，要想功能全还是用jackson吧。