本来想学习一下@RequestBody这个注解，但发请求时出现跨域问题，所以就先来看一下跨域该怎么办。
CORS
首先因为最近在做一个前后端分离的项目，分开就意味着可能不在一个域中，所以不可避免的遇到CORS的问题。试过几个方法：
- Spring MVC 4.2.5以后新增的支持跨域的注解@CrossOrigin，如果是老项目的话升级spring库可能会有些兼容的问题，不知为什么这个注解没有升效;
- 用反向代理，这个一定好使的;
-
还有就是我现在使用的，手动增加一个Filter，在Response中增加对跨域的支持，这种方式对老浏览器可能会有问题。
CORSFilter.Java
public class CORSFilter implements Filter { public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException { HttpServletResponse response = (HttpServletResponse) res; response.setHeader("Access-Control-Allow-Origin", "*"); response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE"); response.setHeader("Access-Control-Max-Age", "3600"); response.addHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept"); chain.doFilter(req, res); } public void init(FilterConfig filterConfig) {} public void destroy() {} }- 1
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web.xml
<filter>
<filter-name>cors</filter-name>
<filter-class>xxxx.CORSFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>cors</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
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如此即可解决跨域问题。
@RequestBody
下面说说@RequestBody这个注解。因为一直觉得传简单对象直接不用注解也可以自动组装，就以为spring可以为我们组装所有类型的对象。但今天测试过，原来象Map,List或复合对象都必需使用这个注解才可以正确组装，以下是我的测试代码：
首先写个测试的Controller:
RequestBodyController.java
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletResponse;
import org.cunframework.core.common.controller.BaseController;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import com.alibaba.fastjson.JSON;
class A{
private String name;
private String value;
public String getName() {
return name;
}
public String getValue() {
return value;
}
public void setName(String name) {
this.name = name;
}
public void setValue(String value) {
this.value = value;
}
}
class B{
private List<A> a;
private String count;
public List<A> getA() {
return a;
}
public String getCount() {
return count;
}
public void setA(List<A> a) {
this.a = a;
}
public void setCount(String count) {
this.count = count;
}
}
@Scope("prototype")
@Controller
@RequestMapping("/rb")
public class RequestBodyController extends BaseController{
@RequestMapping(value = "test1")
@ResponseBody
public Map test1(A a,HttpServletResponse response) {
try {
System.out.println(JSON.toJSONString(a));
return toSuccess();
} catch (Exception e) {
e.printStackTrace();
return toError();
}
}
@RequestMapping(value = "test2")
@ResponseBody
public Map test2(List<A> a,HttpServletResponse response) {
try {
System.out.println(JSON.toJSONString(a));
return toSuccess();
} catch (Exception e) {
e.printStackTrace();
return toError();
}
}
@RequestMapping(value = "test3")
@ResponseBody
public Map test3(@RequestBody List<A> a,HttpServletResponse response) {
try {
System.out.println(JSON.toJSONString(a));
return toSuccess();
} catch (Exception e) {
e.printStackTrace();
return toError();
}
}
@RequestMapping(value = "test4")
@ResponseBody
public Map test4(B b,HttpServletResponse response) {
try {
System.out.println(JSON.toJSONString(b));
return toSuccess();
} catch (Exception e) {
e.printStackTrace();
return toError();
}
}
@RequestMapping(value = "test5")
@ResponseBody
public Map test5(@RequestBody B b,HttpServletResponse response) {
try {
System.out.println(JSON.toJSONString(b));
return toSuccess();
} catch (Exception e) {
e.printStackTrace();
return toError();
}
}
}
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测试用的html文件：
test.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<script src="http://lib.sinaapp.com/js/jquery/1.9.1/jquery-1.9.1.min.js"></script>
<script> function ajax(url,data,contentType){ $.ajax({ type: "POST", contentType: contentType, url: url, data: data, success: function(data){ console.log(data); }, error: function(XMLHttpRequest, textStatus, errorThrown) { alert("Error Occured!"); } }); } function test1(){ var data = { name:123, value:456 }; ajax( "http://localhost:8080/orcs/rb/test1.do", data, "application/x-www-form-urlencoded" ) } function test2(){ var data = [ { name:123, value:456 }, { name:222, value:222 }, { name:333, value:444456 } ]; ajax( "http://localhost:8080/orcs/rb/test2.do", data, "application/x-www-form-urlencoded" ); } function test3(){ var data = [ { name:123, value:456 }, { name:222, value:222 }, { name:333, value:444456 } ]; ajax( "http://localhost:8080/orcs/rb/test3.do", JSON.stringify(data), "application/json" ); } function test4(){ var data = { a:[{ name:123, value:456 }, { name:222, value:222 }, { name:333, value:444456 }], count:222 } ajax( "http://localhost:8080/orcs/rb/test4.do", data, "application/x-www-form-urlencoded" ); } function test5(){ var data = { a:[{ name:123, value:456 }, { name:222, value:222 }, { name:333, value:444456 }], count:222 }; ajax( "http://localhost:8080/orcs/rb/test5.do", JSON.stringify(data), "application/json" ); } </script>
</head>
<body>
<button onclick="test1()">btn1</button>
<button onclick="test2()">btn2</button>
<button onclick="test3()">btn3</button>
<button onclick="test4()">btn4</button>
<button onclick="test5()">btn5</button>
</body>
</html>
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发现@RequestBody这个注解，使用时对ajax有些要求：
- 数据必需要用
JSON.stringify(data)处理; contentType类型必需为application/json。
而不加这个注解组装简单对象时，则：
1. 数据直接用json不必处理;
2. contentType类型默认为application/x-www-form-urlencoded即可。
因为没有深入研究，有不对的地方请指出 :)