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\"?>\r\n<o><id type=\"number\">1</id><name type=\"string\">张三</name></o>\r\n", 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\"?>\r\n<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>\r\n", 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; } } }